qiskit/circuit/compositegate.py
def c_if(self, classical, val):
        """Add classical control register."""
        self.data = [gate.c_if(classical, val) for gate in self.data]
        return self
def c_if(self, classical, val):
        """Add classical control register."""
        self.data = [gate.c_if(classical, val) for gate in self.data]
        return self
Add classical control register.