Alessandro's suggestion

src/qibo/models/circuit.py

@@ -1268,7 +1268,7 @@ def _update_draw_matrix(self, matrix, idx, gate, gate_symbol=None):
 
         return matrix, idx
 
-    def __str__(self, line_wrap: int = 70, legend: bool = False) -> str:
+    def _diagram(self, line_wrap: int = 70, legend: bool = False) -> str:
         # build string representation of gates
         matrix = [[] for _ in range(self.nqubits)]
         idx = [0] * self.nqubits
@@ -1360,6 +1360,9 @@ def chunkstring(string, length):
 
         return output.rstrip("\n")
 
+    def __str__(self):
+        return self._diagram()
+
     def draw(self, line_wrap: int = 70, legend: bool = False):
         """Draw text circuit using unicode symbols.
 
@@ -1380,7 +1383,7 @@ def draw(self, line_wrap: int = 70, legend: bool = False):
             + "In release 0.2.12, the in-place print of circuits is accessible as "
             + "``Circuit._display``."
         )
-        return self.__str__(line_wrap, legend)
+        return self._diagram(line_wrap, legend)
 
     def _display(self, line_wrap: int = 70, legend: bool = False):
         """Draw text circuit using unicode symbols.
@@ -1395,4 +1398,4 @@ def _display(self, line_wrap: int = 70, legend: bool = False):
         Returns:
             String containing text circuit diagram.
         """
-        sys.stdout.write(self.__str__(line_wrap, legend))
+        sys.stdout.write(self._diagram(line_wrap, legend))