qiskit/dagcircuit/dagcircuit.py
def _check_condition(self, name, condition):
        """Verify that the condition is valid.

        Args:
            name (string): used for error reporting
            condition (tuple or None): a condition tuple (ClassicalRegister,int)

        Raises:
            DAGCircuitError: if conditioning on an invalid register
        """
        # Verify creg exists
        if condition is not None and condition[0].name not in self.cregs:
            raise DAGCircuitError("invalid creg in condition for %s" % name)
def _check_condition(self, name, condition):
        # Verify creg exists
        if condition is not None and condition[0].name not in self.cregs:
            raise DAGCircuitError("invalid creg in condition for %s" % name)
def _check_condition ( self , name , condition ) : # Verify creg exists if condition is not None and condition [ 0 ] . name not in self . cregs : raise DAGCircuitError ( "invalid creg in condition for %s" % name )
Verify that the condition is valid.

        Args:
            name (string): used for error reporting
            condition (tuple or None): a condition tuple (ClassicalRegister,int)

        Raises:
            DAGCircuitError: if conditioning on an invalid register
Verify that the condition is valid .