From 184b236a27ca1f4ebeb39aa18a3624bd4fc22837 Mon Sep 17 00:00:00 2001
From: T-Nicholls <tobyn.nicholls@diamond.ac.uk>
Date: Tue, 21 Aug 2018 16:46:14 +0100
Subject: [PATCH 01/10] Add field exception, raised when the entered field does
 not exist on a device, and update comments to reflect addition.

---
 pytac/element.py | 10 ++++++++++
 pytac/model.py   | 21 +++++++++++++++++++--
 2 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/pytac/element.py b/pytac/element.py
index 47401473..c950f9b8 100644
--- a/pytac/element.py
+++ b/pytac/element.py
@@ -1,6 +1,7 @@
 """Module containing the element class."""
 import pytac
 from pytac.device import DeviceException
+from pytac.model import FieldException
 
 
 class Element(object):
@@ -161,6 +162,7 @@ def get_value(self, field, handle=pytac.RB, units=pytac.ENG,
 
         Raises:
             DeviceException: if there is no device on the given field.
+            FieldException: if the element does not have the specified field.
         """
         try:
             model = self._models[model]
@@ -170,6 +172,8 @@ def get_value(self, field, handle=pytac.RB, units=pytac.ENG,
         except KeyError:
             raise DeviceException('No model type {} on element {}'.format(model,
                                                                           self))
+        except FieldException:
+            raise FieldException('No field {} on element {}'.format(field, self))
 
     def set_value(self, field, value, handle=pytac.SP, units=pytac.ENG,
                   model=pytac.LIVE):
@@ -187,6 +191,7 @@ def set_value(self, field, value, handle=pytac.SP, units=pytac.ENG,
 
         Raises:
             DeviceException: if arguments are incorrect.
+            FieldException: if the element does not have the specified field.
         """
         if handle != pytac.SP:
             raise DeviceException('Must write using {}'.format(pytac.SP))
@@ -197,6 +202,8 @@ def set_value(self, field, value, handle=pytac.SP, units=pytac.ENG,
         except KeyError:
             raise DeviceException('No model type {} on element {}'.format(model,
                                                                           self))
+        except FieldException:
+            raise FieldException('No field {} on element {}'.format(field, self))
 
     def get_pv_name(self, field, handle):
         """Get a PV name on a device.
@@ -210,9 +217,12 @@ def get_pv_name(self, field, handle):
 
         Raises:
             DeviceException: if there is no device for this field.
+            FieldException: if the element does not have the specified field.
         """
         try:
             return self._models[pytac.LIVE].get_pv_name(field, handle)
         except KeyError:
             raise DeviceException('{} has no device for field {}'.format(self,
                                                                          field))
+        except FieldException:
+            raise FieldException('No field {} on element {}'.format(field, self))
diff --git a/pytac/model.py b/pytac/model.py
index 5b9f720f..a01fa6fc 100644
--- a/pytac/model.py
+++ b/pytac/model.py
@@ -2,6 +2,11 @@
 import pytac
 
 
+class FieldException(Exception):
+    '''Exception associated with invalid field requests.'''
+    pass
+
+
 class Model(object):
     """Abstract base classes for element models.
 
@@ -116,8 +121,14 @@ def get_value(self, field, handle):
 
         Returns:
             float: The value of the PV.
+
+        Raises:
+            FieldException: if the device does not have the specified field.
         """
-        return self._devices[field].get_value(handle)
+        try:
+            return self._devices[field].get_value(handle)
+        except KeyError:
+            raise FieldException('No field {} on device {}'.format(field, self))
 
     def set_value(self, field, value):
         """Set the value of a readback or setpoint PV for a field from the
@@ -126,5 +137,11 @@ def set_value(self, field, value):
         Args:
             field (str): field for the requested value.
             value (float): The value to set on the PV.
+
+        Raises:
+            FieldException: if the device does not have the specified field.
         """
-        self._devices[field].set_value(value)
+        try:
+            self._devices[field].set_value(value)
+        except KeyError:
+            raise FieldException('No field {} on device {}'.format(field, self))

From 13511eae0f56c3d7593271bd83a6263a2107d1cc Mon Sep 17 00:00:00 2001
From: T-Nicholls <tobyn.nicholls@diamond.ac.uk>
Date: Tue, 21 Aug 2018 17:53:05 +0100
Subject: [PATCH 02/10] Add handle exception, raised when an invalid handle is
 used.

---
 pytac/device.py  | 12 +++++++++---
 pytac/element.py | 11 +++++++----
 pytac/model.py   |  3 ++-
 3 files changed, 18 insertions(+), 8 deletions(-)

diff --git a/pytac/device.py b/pytac/device.py
index 5a81d77c..39bf849a 100644
--- a/pytac/device.py
+++ b/pytac/device.py
@@ -8,6 +8,12 @@
 import pytac
 
 
+class HandleException(Exception):
+    """Exception associated with requests with invalid handles.
+    """
+    pass
+
+
 class DeviceException(Exception):
     """Exception associated with Device misconfiguration or invalid requests.
     """
@@ -73,7 +79,7 @@ def set_value(self, value):
             DeviceException: if no setpoint PV exists.
         """
         if self.sp_pv is None:
-            raise DeviceException("""Device {0} has no setpoint PV."""
+            raise HandleException("""Device {0} has no setpoint PV."""
                               .format(self.name))
         self._cs.put(self.sp_pv, value)
 
@@ -96,7 +102,7 @@ def get_value(self, handle):
         elif handle == pytac.SP and self.sp_pv:
             return self._cs.get(self.sp_pv)
 
-        raise DeviceException("""Device {0} has no {1} PV."""
+        raise HandleException("""Device {0} has no {1} PV."""
                           .format(self.name, handle))
 
     def get_pv_name(self, handle):
@@ -116,7 +122,7 @@ def get_pv_name(self, handle):
         elif handle == pytac.SP and self.sp_pv:
             return self.sp_pv
 
-        raise DeviceException("""Device {0} has no {1} PV."""
+        raise HandleException("""Device {0} has no {1} PV."""
                           .format(self.name, handle))
 
     def get_cs(self):
diff --git a/pytac/element.py b/pytac/element.py
index c950f9b8..5c4bff0a 100644
--- a/pytac/element.py
+++ b/pytac/element.py
@@ -1,6 +1,6 @@
 """Module containing the element class."""
 import pytac
-from pytac.device import DeviceException
+from pytac.device import DeviceException, HandleException
 from pytac.model import FieldException
 
 
@@ -194,14 +194,17 @@ def set_value(self, field, value, handle=pytac.SP, units=pytac.ENG,
             FieldException: if the element does not have the specified field.
         """
         if handle != pytac.SP:
-            raise DeviceException('Must write using {}'.format(pytac.SP))
+            raise HandleException('Must write using {}'.format(pytac.SP))
         try:
             model = self._models[model]
-            value = self._uc[field].convert(value, origin=units, target=model.units)
-            model.set_value(field, value)
         except KeyError:
             raise DeviceException('No model type {} on element {}'.format(model,
                                                                           self))
+        try:            
+            value = self._uc[field].convert(value, origin=units, target=model.units)
+            model.set_value(field, value)
+        except KeyError:
+            raise FieldException('No field {} on element {}'.format(model, self))
         except FieldException:
             raise FieldException('No field {} on element {}'.format(field, self))
 
diff --git a/pytac/model.py b/pytac/model.py
index a01fa6fc..48574c06 100644
--- a/pytac/model.py
+++ b/pytac/model.py
@@ -3,7 +3,8 @@
 
 
 class FieldException(Exception):
-    '''Exception associated with invalid field requests.'''
+    """Exception associated with invalid field requests.
+    """
     pass
 
 

From f5d8e8ff29239cb122b5bfcae5d0fbfaf414ea5f Mon Sep 17 00:00:00 2001
From: T-Nicholls <tobyn.nicholls@diamond.ac.uk>
Date: Tue, 21 Aug 2018 17:54:39 +0100
Subject: [PATCH 03/10] Update test_element to work with new handles and create
 separate get and set tests.

---
 test/test_element.py | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/test/test_element.py b/test/test_element.py
index 93b09dad..79145431 100644
--- a/test/test_element.py
+++ b/test/test_element.py
@@ -106,16 +106,22 @@ def test_set_value_phys(test_element):
                                                             (DUMMY_VALUE_2 / 2))
 
 
-def test_set_value_incorrect_field(test_element):
+def test_set_exceptions(test_element):
+    with pytest.raises(pytac.model.FieldException):
+        test_element.set_value('unknown_field', 40.0, 'setpoint')
+    with pytest.raises(pytac.device.HandleException):
+        test_element.set_value('y', 40.0, 'unknown_handle')
     with pytest.raises(pytac.device.DeviceException):
-        test_element.set_value('non_existent', 40.0)
+        test_element.set_value('y', 40.0, 'setpoint', model='unknown_model')
 
 
-def test_get_pv_exceptions(test_element):
+def test_get_exceptions(test_element):
+    with pytest.raises(pytac.model.FieldException):
+        test_element.get_value('unknown_field', 'setpoint')
+    with pytest.raises(pytac.device.HandleException):
+        test_element.get_value('y', 'unknown_handle')
     with pytest.raises(pytac.device.DeviceException):
-        test_element.get_value('setpoint', 'unknown_field')
-    with pytest.raises(pytac.device.DeviceException):
-        test_element.get_value('unknown_handle', 'y')
+        test_element.get_value('y', 'setpoint', model='unknown_model')
 
 
 def test_identity_conversion():

From 4b568d78bb106cff16d20f442793fef890b7d029 Mon Sep 17 00:00:00 2001
From: T-Nicholls <tobyn.nicholls@diamond.ac.uk>
Date: Wed, 22 Aug 2018 09:13:19 +0100
Subject: [PATCH 04/10] Correct DeviceException to HandleException in comments
 where relevant.

---
 pytac/device.py | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/pytac/device.py b/pytac/device.py
index 39bf849a..42486e32 100644
--- a/pytac/device.py
+++ b/pytac/device.py
@@ -76,7 +76,7 @@ def set_value(self, value):
             value (float): The value to set on the PV.
 
         Raises:
-            DeviceException: if no setpoint PV exists.
+            HandleException: if no setpoint PV exists.
         """
         if self.sp_pv is None:
             raise HandleException("""Device {0} has no setpoint PV."""
@@ -94,7 +94,7 @@ def get_value(self, handle):
             float: The value of the PV.
 
         Raises:
-            DeviceException: if the requested PV doesn't exist.
+            HandleException: if the requested PV doesn't exist.
         """
         print('getting {}'.format('handle'))
         if handle == pytac.RB and self.rb_pv:
@@ -115,7 +115,7 @@ def get_pv_name(self, handle):
             str: A readback or setpoint PV.
 
         Raises:
-            DeviceException: if the PV doesn't exist.
+            HandleException: if the PV doesn't exist.
         """
         if handle == pytac.RB and self.rb_pv:
             return self.rb_pv

From 5fc940e905e995cbc8a548547c4f1520a88b7ae0 Mon Sep 17 00:00:00 2001
From: T-Nicholls <tobyn.nicholls@diamond.ac.uk>
Date: Wed, 22 Aug 2018 09:17:55 +0100
Subject: [PATCH 05/10] Update test files inline with changes to exceptions
 raised in the code.

---
 test/test_device.py  | 4 ++--
 test/test_machine.py | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/test/test_device.py b/test/test_device.py
index 9924a3c2..91dcd5cf 100644
--- a/test/test_device.py
+++ b/test/test_device.py
@@ -21,13 +21,13 @@ def test_set_device_value():
 
 def test_device_invalid_sp_raise_exception():
     device2 = create_device(PREFIX, RB_PV, None)
-    with pytest.raises(pytac.device.DeviceException):
+    with pytest.raises(pytac.device.HandleException):
         device2.set_value(40)
 
 
 def test_get_device_value():
     device = create_device()
-    with pytest.raises(pytac.device.DeviceException):
+    with pytest.raises(pytac.device.HandleException):
         device.get_value('non_existent')
 
 
diff --git a/test/test_machine.py b/test/test_machine.py
index 83d96b12..7e7849f4 100644
--- a/test/test_machine.py
+++ b/test/test_machine.py
@@ -63,7 +63,7 @@ def test_load_bpms(ring_mode, n_bpms):
                  'y_fofb_disabled', 'y_sofb_disabled')
         )
         assert re.match('SR.*BPM.*X', bpm.get_pv_name('x', pytac.RB))
-        with pytest.raises(pytac.device.DeviceException):
+        with pytest.raises(pytac.device.HandleException):
             bpm.get_pv_name('x', pytac.SP)
     assert len(bpms) == n_bpms
     assert bpms[0].cell == 1

From 34a30a29d5f0bd6b29c0f7476fdb1e91d8aad877 Mon Sep 17 00:00:00 2001
From: T-Nicholls <tobyn.nicholls@diamond.ac.uk>
Date: Wed, 22 Aug 2018 09:23:01 +0100
Subject: [PATCH 06/10] Fix trailing whitespace after try: in element.py.

---
 pytac/element.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pytac/element.py b/pytac/element.py
index 5c4bff0a..df85ab03 100644
--- a/pytac/element.py
+++ b/pytac/element.py
@@ -200,7 +200,7 @@ def set_value(self, field, value, handle=pytac.SP, units=pytac.ENG,
         except KeyError:
             raise DeviceException('No model type {} on element {}'.format(model,
                                                                           self))
-        try:            
+        try:
             value = self._uc[field].convert(value, origin=units, target=model.units)
             model.set_value(field, value)
         except KeyError:

From 676de767cce7513312e5f70ac52df1b86949886f Mon Sep 17 00:00:00 2001
From: T-Nicholls <tobyn.nicholls@diamond.ac.uk>
Date: Wed, 22 Aug 2018 15:39:08 +0100
Subject: [PATCH 07/10] Resolve merge conflict.

---
 pytac/device.py | 21 +++------------------
 1 file changed, 3 insertions(+), 18 deletions(-)

diff --git a/pytac/device.py b/pytac/device.py
index 2516e80c..44d3d483 100644
--- a/pytac/device.py
+++ b/pytac/device.py
@@ -79,14 +79,9 @@ def set_value(self, value):
             HandleException: if no setpoint PV exists.
         """
         if self.sp_pv is None:
-<<<<<<< HEAD
-            raise HandleException("""Device {0} has no setpoint PV."""
-                              .format(self.name))
-=======
-            raise DeviceException(
+            raise HandleException(
                 "Device {0} has no setpoint PV.".format(self.name)
             )
->>>>>>> 106930cd6a2dd86a1533bf73d03c4ef14bd72e49
         self._cs.put(self.sp_pv, value)
 
     def get_value(self, handle):
@@ -108,14 +103,9 @@ def get_value(self, handle):
         elif handle == pytac.SP and self.sp_pv:
             return self._cs.get(self.sp_pv)
 
-<<<<<<< HEAD
-        raise HandleException("""Device {0} has no {1} PV."""
-                          .format(self.name, handle))
-=======
-        raise DeviceException(
+        raise HandleException(
             "Device {0} has no {1} PV.".format(self.name, handle)
         )
->>>>>>> 106930cd6a2dd86a1533bf73d03c4ef14bd72e49
 
     def get_pv_name(self, handle):
         """Get a PV name on a specified handle.
@@ -134,14 +124,9 @@ def get_pv_name(self, handle):
         elif handle == pytac.SP and self.sp_pv:
             return self.sp_pv
 
-<<<<<<< HEAD
-        raise HandleException("""Device {0} has no {1} PV."""
-                          .format(self.name, handle))
-=======
-        raise DeviceException(
+        raise HandleException(
             "Device {0} has no {1} PV.".format(self.name, handle)
         )
->>>>>>> 106930cd6a2dd86a1533bf73d03c4ef14bd72e49
 
     def get_cs(self):
         """The control system object used to get and set the value of a PV.

From 1bf0728f17dbace0915f8ae9715425a2912b5b10 Mon Sep 17 00:00:00 2001
From: T-Nicholls <tobyn.nicholls@diamond.ac.uk>
Date: Wed, 22 Aug 2018 16:07:20 +0100
Subject: [PATCH 08/10] Move all exceptions to thier own files and update their
 call accordingly.

---
 pytac/device.py      | 13 +------------
 pytac/element.py     |  3 +--
 pytac/lattice.py     |  5 +----
 pytac/model.py       |  8 +-------
 pytac/units.py       |  7 +------
 test/test_device.py  |  4 ++--
 test/test_element.py | 12 ++++++------
 test/test_lattice.py |  4 ++--
 test/test_machine.py |  4 ++--
 test/test_units.py   |  3 ++-
 10 files changed, 19 insertions(+), 44 deletions(-)

diff --git a/pytac/device.py b/pytac/device.py
index 44d3d483..631988e7 100644
--- a/pytac/device.py
+++ b/pytac/device.py
@@ -6,18 +6,7 @@
 magnets and a skew quadrupole.
 """
 import pytac
-
-
-class HandleException(Exception):
-    """Exception associated with requests with invalid handles.
-    """
-    pass
-
-
-class DeviceException(Exception):
-    """Exception associated with Device misconfiguration or invalid requests.
-    """
-    pass
+from pytac.exceptions import HandleException
 
 
 class Device(object):
diff --git a/pytac/element.py b/pytac/element.py
index df85ab03..8b4342d9 100644
--- a/pytac/element.py
+++ b/pytac/element.py
@@ -1,7 +1,6 @@
 """Module containing the element class."""
 import pytac
-from pytac.device import DeviceException, HandleException
-from pytac.model import FieldException
+from pytac.exceptions import FieldException, HandleException, DeviceException
 
 
 class Element(object):
diff --git a/pytac/lattice.py b/pytac/lattice.py
index 021e524b..f0585369 100644
--- a/pytac/lattice.py
+++ b/pytac/lattice.py
@@ -2,10 +2,7 @@
     machine.
 """
 import numpy
-
-
-class LatticeException(Exception):
-    pass
+from pytac.exceptions import LatticeException
 
 
 class Lattice(object):
diff --git a/pytac/model.py b/pytac/model.py
index 48574c06..5839720e 100644
--- a/pytac/model.py
+++ b/pytac/model.py
@@ -1,12 +1,6 @@
 """Module containing pytac model classes."""
 import pytac
-
-
-class FieldException(Exception):
-    """Exception associated with invalid field requests.
-    """
-    pass
-
+from pytac.exceptions import FieldException
 
 class Model(object):
     """Abstract base classes for element models.
diff --git a/pytac/units.py b/pytac/units.py
index 6ce60ac5..a70e6f4c 100644
--- a/pytac/units.py
+++ b/pytac/units.py
@@ -1,15 +1,10 @@
 """Classes for use in unit conversion."""
 import pytac
 import numpy
+from pytac.exceptions import UnitsException
 from scipy.interpolate import PchipInterpolator
 
 
-class UnitsException(Exception):
-    """Conversion not understood
-    """
-    pass
-
-
 def unit_function(value):
     """Default value for the pre and post functions used in unit conversion.
 
diff --git a/test/test_device.py b/test/test_device.py
index 12c379a7..8bfb3370 100644
--- a/test/test_device.py
+++ b/test/test_device.py
@@ -22,13 +22,13 @@ def test_set_device_value():
 
 def test_device_invalid_sp_raise_exception():
     device2 = create_device(PREFIX, RB_PV, None)
-    with pytest.raises(pytac.device.HandleException):
+    with pytest.raises(pytac.exceptions.HandleException):
         device2.set_value(40)
 
 
 def test_get_device_value():
     device = create_device()
-    with pytest.raises(pytac.device.HandleException):
+    with pytest.raises(pytac.exceptions.HandleException):
         device.get_value('non_existent')
 
 
diff --git a/test/test_element.py b/test/test_element.py
index 79145431..897d9eb8 100644
--- a/test/test_element.py
+++ b/test/test_element.py
@@ -107,20 +107,20 @@ def test_set_value_phys(test_element):
 
 
 def test_set_exceptions(test_element):
-    with pytest.raises(pytac.model.FieldException):
+    with pytest.raises(pytac.exceptions.FieldException):
         test_element.set_value('unknown_field', 40.0, 'setpoint')
-    with pytest.raises(pytac.device.HandleException):
+    with pytest.raises(pytac.exceptions.HandleException):
         test_element.set_value('y', 40.0, 'unknown_handle')
-    with pytest.raises(pytac.device.DeviceException):
+    with pytest.raises(pytac.exceptions.DeviceException):
         test_element.set_value('y', 40.0, 'setpoint', model='unknown_model')
 
 
 def test_get_exceptions(test_element):
-    with pytest.raises(pytac.model.FieldException):
+    with pytest.raises(pytac.exceptions.FieldException):
         test_element.get_value('unknown_field', 'setpoint')
-    with pytest.raises(pytac.device.HandleException):
+    with pytest.raises(pytac.exceptions.HandleException):
         test_element.get_value('y', 'unknown_handle')
-    with pytest.raises(pytac.device.DeviceException):
+    with pytest.raises(pytac.exceptions.DeviceException):
         test_element.get_value('y', 'setpoint', model='unknown_model')
 
 
diff --git a/test/test_lattice.py b/test/test_lattice.py
index 576fa9b1..950c97af 100644
--- a/test/test_lattice.py
+++ b/test/test_lattice.py
@@ -129,7 +129,7 @@ def test_set_values(simple_element_and_lattice):
 
 def test_set_values_raise_exception_if_number_of_values_does_not_match(simple_element_and_lattice):
     element, lattice = simple_element_and_lattice
-    with pytest.raises(pytac.lattice.LatticeException):
+    with pytest.raises(pytac.exceptions.LatticeException):
         lattice.set_values('family', 'x', [1, 2])
 
 
@@ -149,7 +149,7 @@ def test_s_position(simple_element_and_lattice):
 def test_get_s_throws_exception_if_element_not_in_lattice():
     lat = pytac.lattice.Lattice(LATTICE, mock.MagicMock(), 1)
     element = pytac.element.Element(1, 1.0, 'Quad')
-    with pytest.raises(pytac.lattice.LatticeException):
+    with pytest.raises(pytac.exceptions.LatticeException):
         lat.get_s(element)
 
 
diff --git a/test/test_machine.py b/test/test_machine.py
index 71df2787..d37ecc3e 100644
--- a/test/test_machine.py
+++ b/test/test_machine.py
@@ -67,7 +67,7 @@ def test_load_bpms(ring_mode, n_bpms):
     for bpm in bpms:
         assert set(bpm.get_fields()) == bpm_fields
         assert re.match('SR.*BPM.*X', bpm.get_pv_name('x', pytac.RB))
-        with pytest.raises(pytac.device.HandleException):
+        with pytest.raises(pytac.exceptions.HandleException):
             bpm.get_pv_name('x', pytac.SP)
     assert len(bpms) == n_bpms
     assert bpms[0].cell == 1
@@ -184,7 +184,7 @@ def test_quad_unitconv():
 
 def test_quad_unitconv_raise_exception():
     uc = pytac.units.PchipUnitConv([50.0, 100.0, 180.0], [-4.95, -9.85, -17.56])
-    with pytest.raises(pytac.units.UnitsException):
+    with pytest.raises(pytac.exceptions.UnitsException):
         uc.phys_to_eng(-0.7)
 
 
diff --git a/test/test_units.py b/test/test_units.py
index 35782ffd..9bad8a84 100644
--- a/test/test_units.py
+++ b/test/test_units.py
@@ -1,6 +1,7 @@
 import pytest
 import pytac
-from pytac.units import UnitConv, PolyUnitConv, PchipUnitConv, UnitsException
+from pytac.units import UnitConv, PolyUnitConv, PchipUnitConv
+from pytac.exceptions import UnitsException
 import numpy
 
 

From 978e6c06714315616253f254f0431ec6f0cc98dc Mon Sep 17 00:00:00 2001
From: T-Nicholls <tobyn.nicholls@diamond.ac.uk>
Date: Wed, 22 Aug 2018 16:31:17 +0100
Subject: [PATCH 09/10] Add exceptions file to repository.

---
 pytac/exceptions.py | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)
 create mode 100644 pytac/exceptions.py

diff --git a/pytac/exceptions.py b/pytac/exceptions.py
new file mode 100644
index 00000000..9e5dccd1
--- /dev/null
+++ b/pytac/exceptions.py
@@ -0,0 +1,24 @@
+"""Module containing all the exceptions used in pytac."""
+
+class FieldException(Exception):
+    """Exception associated with invalid field requests.
+    """
+    pass
+
+class HandleException(Exception):
+    """Exception associated with requests with invalid handles.
+    """
+    pass
+
+class DeviceException(Exception):
+    """Exception associated with Device misconfiguration or invalid requests.
+    """
+    pass
+
+class UnitsException(Exception):
+    """Conversion not understood
+    """
+    pass
+
+class LatticeException(Exception):
+    pass

From 934e26ff7dd07c4a2b933a2a640ee12a2f9b0e4b Mon Sep 17 00:00:00 2001
From: T-Nicholls <tobyn.nicholls@diamond.ac.uk>
Date: Wed, 22 Aug 2018 17:07:51 +0100
Subject: [PATCH 10/10] Correct two files to be inline with pep8 standards.

---
 pytac/exceptions.py | 5 +++++
 pytac/model.py      | 1 +
 2 files changed, 6 insertions(+)

diff --git a/pytac/exceptions.py b/pytac/exceptions.py
index 9e5dccd1..60f67e8b 100644
--- a/pytac/exceptions.py
+++ b/pytac/exceptions.py
@@ -1,24 +1,29 @@
 """Module containing all the exceptions used in pytac."""
 
+
 class FieldException(Exception):
     """Exception associated with invalid field requests.
     """
     pass
 
+
 class HandleException(Exception):
     """Exception associated with requests with invalid handles.
     """
     pass
 
+
 class DeviceException(Exception):
     """Exception associated with Device misconfiguration or invalid requests.
     """
     pass
 
+
 class UnitsException(Exception):
     """Conversion not understood
     """
     pass
 
+
 class LatticeException(Exception):
     pass
diff --git a/pytac/model.py b/pytac/model.py
index 5839720e..475f433e 100644
--- a/pytac/model.py
+++ b/pytac/model.py
@@ -2,6 +2,7 @@
 import pytac
 from pytac.exceptions import FieldException
 
+
 class Model(object):
     """Abstract base classes for element models.