def get_pull_command(self, remote=None, revision=None):
raise NotImplementedError()<EOL>
Get the command to pull changes from a remote repository into the local repository.

:param remote: The location of a remote repository (a string or :data:`None`).
:param revision: A specific revision to pull (a string or :data:`None`).
:returns: A list of strings.

This method needs to be implemented by subclasses.