Returns plugin or plugin point class from given ``plugin_name`` string.

    Example of ``plugin_name``::

        'my_app.MyPlugin'

def get_plugin_from_string(plugin_name):
    """
    Returns plugin or plugin point class from given ``plugin_name`` string.

    Example of ``plugin_name``::

        'my_app.MyPlugin'

    """
    modulename, classname = plugin_name.rsplit('.', 1)
    module = import_module(modulename)
    return getattr(module, classname)