qiskit/quantum_info/operators/channel/quantum_channel.py
def is_unitary(self, atol=None, rtol=None):
        """Return True if QuantumChannel is a unitary channel."""
        try:
            op = self.to_operator()
            return op.is_unitary(atol=atol, rtol=rtol)
        except QiskitError:
            return False
def is_unitary(self, atol=None, rtol=None):
        """Return True if QuantumChannel is a unitary channel."""
        try:
            op = self.to_operator()
            return op.is_unitary(atol=atol, rtol=rtol)
        except QiskitError:
            return False
Return True if QuantumChannel is a unitary channel.