docs: def dir_contains(dirname, path, exists=True):
      """Check if a file of directory is contained in another.
  
      Parameters
      ----------
      dirname: str
          The base directory that should contain `path`
      path: str
          The name of a directory or file that should be in `dirname`
      exists: bool
          If True, the `path` and `dirname` must exist
  
      Notes
      -----
      `path` and `dirname` must be either both absolute or both relative
      paths"""
      if exists:
          dirname = osp.abspath(dirname)
          path = osp.abspath(path)
          if six.PY2 or six.PY34:
              return osp.exists(path) and osp.samefile(
                  osp.commonprefix([dirname, path]), dirname)
          else:
              return osp.samefile(osp.commonpath([dirname, path]), dirname)
      return dirname in osp.commonprefix([dirname, path])