'Fetch file over scp from remote device'

def fetch_file(self, source, destination):

    if (not HAS_SCP):
        self._connection.internal_error('Required    library    scp    is    not    installed.        Please    install    it    using    `pip    install    scp`')
    ssh = self._connection._connect_uncached()
    with SCPClient(ssh.get_transport()) as scp:
        scp.get(source, destination)
