def register_function(self, function_name, function):
my_info = self._get_module_info(self._module.module_full_name)<EOL>my_info[function_name] = function<EOL>
Register a function for the module.

The following functions can be registered


    ..  py:function:: content_function()

    Called to discover what modules a container is displaying.  This is
    used to determine when updates need passing on to the container and
    also when modules can be put to sleep.

    the function must return a set of module names that are being
    displayed.

    .. note::

        This function should only be used by containers.

    ..  py:function:: urgent_function(module_names)

    This function will be called when one of the contents of a container
    has changed from a non-urgent to an urgent state.  It is used by the
    group module to switch to displaying the urgent module.

    ``module_names`` is a list of modules that have become urgent

    .. note::

        This function should only be used by containers.