def METHOD_NAME(self):
    """Reads MATLAB ``.mat`` file.
    Returns
    -------
    w : libpysal.weights.W
        A PySAL `W` object.
    Raises
    ------
    StopIteration
        Raised at the EOF.
    Examples
    --------
    Type ``dir(w)`` at the interpreter to see what methods are supported.
    Open a MATLAB ``.mat`` file and read it into a PySAL weights object.
    >>> import libpysal
    >>> w = libpysal.io.open(libpysal.examples.get_path(
    ...     'spat-sym-us.mat'), 'r'
    ... ).read()
    Get the number of observations from the header.
    >>> w.n
    46
    Get the mean number of neighbors.
    >>> w.mean_neighbors
    4.086956521739131
    Get neighbor distances for a single observation.
    >>> w[1] == dict({25: 1, 3: 1, 28: 1, 39: 1})
    True
    """
    if self.pos > 0:
        raise StopIteration
    mat = sio.loadmat(self.file)
    mat_keys = [k for k in mat if not k.startswith("_")]
    full_w = mat[mat_keys[0]]
    self.pos += 1
    w = full2W(full_w)
    return w