add isinstance check
@@ -161,7 +161,7 @@ class BooleanLogicNormalForm(ABC):
@staticmethod
def _set_up_register(num_qubits_needed, provided_register, description):
- if provided_register == 'skip':
+ if isinstance(provided_register, str) and provided_register == 'skip':
return None
else:
if provided_register is None:
