def flowingFrom(fount):
    """
        This drain is now accepting a flow from the given L{IFount}.

        @param fount: A fount, or L{None} if no further input will be received.
        @type fount: L{IFount} or L{types.NoneType}

        @return: another L{IFount}, if this L{IDrain} will produce more data,
            or C{None}.
        """
