def example1():
    """A very basic doctest example.

    Notes
    -----
    The numpy module is imported at the end of this file, in the test::

        if __name__ == "__main__":
            import doctest
            import numpy
            doctest.testmod()

    Examples
    --------
    >>> numpy.array([1, 2, 3])
    array([1, 2, 3])
    """
    pass