diff --git a/n3fit/src/n3fit/backends/keras_backend/operations.py b/n3fit/src/n3fit/backends/keras_backend/operations.py
index e689e892bd..5d7638537f 100644
--- a/n3fit/src/n3fit/backends/keras_backend/operations.py
+++ b/n3fit/src/n3fit/backends/keras_backend/operations.py
@@ -154,7 +154,7 @@ def op_multiply_dim(o_list, **kwargs):
     """
     if len(o_list) != 2:
         raise ValueError(
-            "The number of observables is incorrect, operations.py:op_multiply_dim, expected 2, received {0}".format(
+            "The number of observables is incorrect, operations.py:op_multiply_dim, expected 2, received {}".format(
                 len(o_list)
             )
         )
@@ -309,7 +309,7 @@ def pow(tensor, power):
     return tf.pow(tensor, power)
 
 
-@tf.function(experimental_relax_shapes=True)
+@tf.function(reduce_retracing=True)
 def op_log(o_tensor, **kwargs):
     """
     Computes the logarithm of the input
diff --git a/validphys2/src/validphys/config.py b/validphys2/src/validphys/config.py
index 1b6ba79cf8..d59372c3a7 100644
--- a/validphys2/src/validphys/config.py
+++ b/validphys2/src/validphys/config.py
@@ -1,20 +1,14 @@
-# -*- coding: utf-8 -*-
-"""
-Created on Wed Mar  9 15:43:10 2016
-
-@author: Zahari Kassabov
-"""
 from collections import ChainMap, defaultdict
 from collections.abc import Mapping, Sequence
 import copy
 import functools
-import glob
 from importlib.resources import contents, read_text
 import inspect
 import logging
 import numbers
 import pathlib
 
+from frozendict import frozendict
 import pandas as pd
 
 from reportengine import configparser, report
@@ -45,13 +39,12 @@
 )
 from validphys.paramfits.config import ParamfitsConfig
 from validphys.plotoptions import get_info
-from validphys.utils import freeze_args
-from frozendict import frozendict
 import validphys.scalevariations
-
+from validphys.utils import freeze_args
 
 log = logging.getLogger(__name__)
 
+
 class Environment(Environment):
     """Container for information to be filled at run time"""
 
@@ -709,18 +702,6 @@ def produce_loaded_theory_covmat(
                 generic_path = "datacuts_theory_theorycovmatconfig_total_theory_covmat.csv"
             else:
                 generic_path = "datacuts_theory_theorycovmatconfig_user_covmat.csv"
-        # check if there are multiple files
-        files = glob.glob(str(output_path / "tables/*theorycovmat*"))
-        paths = [
-            str(output_path / "tables/datacuts_theory_theorycovmatconfig_theory_covmat_custom.csv"),
-            str(output_path / "tables/datacuts_theory_theorycovmatconfig_total_theory_covmat.csv"),
-            str(output_path / "tables/datacuts_theory_theorycovmatconfig_user_covmat.csv"),
-        ]
-        paths.remove(str(output_path / "tables" / generic_path))
-        for f in files:
-            for path in paths:
-                if f == path:
-                    raise ValueError("More than one theory_covmat file in folder tables")
         theorypath = output_path / "tables" / generic_path
         theory_covmat = pd.read_csv(
             theorypath, index_col=[0, 1, 2], header=[0, 1, 2], sep="\t|,", engine="python"
@@ -919,9 +900,7 @@ def produce_combined_shift_and_theory_dataspecs(self, dataspecs):
         len_th = len(dataspecs)
         for s in matched_datasets:
             new_dataspecs.append(ChainMap({"dataspecs": s["dataspecs"][len_th:]}, s))
-        return {
-            "dataspecs": {"dataspecs": new_dataspecs, "original": dataspecs },
-        }
+        return {"dataspecs": {"dataspecs": new_dataspecs, "original": dataspecs}}
 
     # TODO: Worth it to do some black magic to not pass params explicitly?
     # Note that `parse_experiments` doesn't exist yet.