@staticmethod<EOL><INDENT>def get_vcs_directory(context, directory):<DEDENT>
raise NotImplementedError()<EOL>
Get the pathname of the directory containing the version control metadata files.

:param context: An execution context created by :mod:`executor.contexts`.
:param directory: The pathname of a directory (a string).
:returns: The pathname of the directory containing the version control
          metadata files (a string). In most cases this will be a
          subdirectory of the given directory, but it may also be the
          directory itself.

This static method needs to be implemented by subclasses:

- If `directory` doesn't exist this should not raise exceptions.
- If `directory` does exist its contents may influence the result of
  :func:`get_vcs_directory()` in order to cope with version control
  backends whose directory layout changes depending on whether they are
  :attr:`bare` (I'm looking at you git).