Return a list of all of the ``Parameter`` objects.

        Or a just a single ``Parameter`` is there is only one, and single empty
        ``Parameter`` if there are no parameters.

def params(self):
        """
        Return a list of all of the ``Parameter`` objects.

        Or a just a single ``Parameter`` is there is only one, and single empty
        ``Parameter`` if there are no parameters.
        """
        paramlist = [b.params for b in self.bases if b.params.has_value]

        if len(paramlist) == 0:
            return Parameter()
        else:
            return paramlist if len(paramlist) > 1 else paramlist[0]