code: def shell_cmd(self, command=""):
          
          if not command:
              raise InvalidCommandError("Parameter 'command' must not be empty.")
          command = command.strip() + '\n'
          self._shell.send(command)
          time.sleep(2)
          out = ''
          while self._shell.recv_ready():
              out += self._shell.recv(999999)
              time.sleep(.75)
          # take off the command being sent and the prompt at the end.
          return '\n'.join(out.split('\n')[1:-1])
docs: Execute a shell command.
  
          Purpose: Used to send a shell command to the connected device.
                 | This uses the self._shell instance, which should be a
                 | paramiko.Channel object, instead of a SSHClient.
                 | This is because we cannot send shell commands to the
                 | device using a SSHClient.
  
          @param command: The single command that to retrieve output from the
                        | device.
          @type command: str
  
          @returns: The reply from the device.
          @rtype: str