Converts a Gate into a Channel

def aschannel(self) -> 'Channel':
        """Converts a Gate into a Channel"""
        N = self.qubit_nb
        R = 4

        tensor = bk.outer(self.tensor, self.H.tensor)
        tensor = bk.reshape(tensor, [2**N]*R)
        tensor = bk.transpose(tensor, [0, 3, 1, 2])

        return Channel(tensor, self.qubits)