qiskit/circuit/quantumcircuit.py
def extend(self, rhs):
        """
        Append rhs to self if self contains compatible registers.

        Two circuits are compatible if they contain the same registers
        or if they contain different registers with unique names. The
        returned circuit will contain all unique registers between both
        circuits.

        Modify and return self.
        """
        # Check registers in LHS are compatible with RHS
        self._check_compatible_regs(rhs)

        # Add new registers
        for element in rhs.qregs:
            if element not in self.qregs:
                self.qregs.append(element)
        for element in rhs.cregs:
            if element not in self.cregs:
                self.cregs.append(element)

        # Add new gates
        for instruction_context in rhs.data:
            self.append(*instruction_context)
        return self
def extend(self, rhs):
        """
        Append rhs to self if self contains compatible registers.

        Two circuits are compatible if they contain the same registers
        or if they contain different registers with unique names. The
        returned circuit will contain all unique registers between both
        circuits.

        Modify and return self.
        """
        # Check registers in LHS are compatible with RHS
        self._check_compatible_regs(rhs)

        # Add new registers
        for element in rhs.qregs:
            if element not in self.qregs:
                self.qregs.append(element)
        for element in rhs.cregs:
            if element not in self.cregs:
                self.cregs.append(element)

        # Add new gates
        for instruction_context in rhs.data:
            self.append(*instruction_context)
        return self
Append rhs to self if self contains compatible registers.

        Two circuits are compatible if they contain the same registers
        or if they contain different registers with unique names. The
        returned circuit will contain all unique registers between both
        circuits.

        Modify and return self.