qiskit/circuit/instructionset.py
def c_if(self, classical, val):
        """Add classical control register to all instructions."""
        for gate in self.instructions:
            gate.c_if(classical, val)
        return self
def c_if(self, classical, val):
        """Add classical control register to all instructions."""
        for gate in self.instructions:
            gate.c_if(classical, val)
        return self
Add classical control register to all instructions.