'Deactivates the specified MFA device and removes it from
association with the user.
:type user_name: string
:param user_name: The username of the user
:type serial_number: string
:param serial_number: The serial number which uniquely identifies
the MFA device.'

def deactivate_mfa_device(self, user_name, serial_number):

    params = {'UserName': user_name, 'SerialNumber': serial_number}
    return self.get_response('DeactivateMFADevice', params)
