Open a file on your local drive, using its extension to guess its type.

    This routine only works on ``.bsp`` ephemeris files right now, but
    will gain support for additional file types in the future. ::

        from skyfield.api import load_file
        planets = load_file('~/Downloads/de421.bsp')

def load_file(path):
    """Open a file on your local drive, using its extension to guess its type.

    This routine only works on ``.bsp`` ephemeris files right now, but
    will gain support for additional file types in the future. ::

        from skyfield.api import load_file
        planets = load_file('~/Downloads/de421.bsp')

    """
    path = os.path.expanduser(path)
    base, ext = os.path.splitext(path)
    if ext == '.bsp':
        return SpiceKernel(path)
    raise ValueError('unrecognized file extension: {}'.format(path))