Create a new L{CssParameter} node as a child of this element, and attach it to the DOM.
        Optionally set the name and value of the parameter, if they are both provided.

        @type   name: string
        @param  name: Optional. The name of the L{CssParameter}
        @type  value: string
        @param value: Optional. The value of the L{CssParameter}
        @rtype: L{CssParameter}
        @return: A new style parameter, set to the name and value.

def create_cssparameter(self, name=None, value=None):
        """
        Create a new L{CssParameter} node as a child of this element, and attach it to the DOM.
        Optionally set the name and value of the parameter, if they are both provided.

        @type   name: string
        @param  name: Optional. The name of the L{CssParameter}
        @type  value: string
        @param value: Optional. The value of the L{CssParameter}
        @rtype: L{CssParameter}
        @return: A new style parameter, set to the name and value.
        """
        elem = self._node.makeelement('{%s}CssParameter' % SLDNode._nsmap['sld'], nsmap=SLDNode._nsmap)
        self._node.append(elem)

        if not (name is None or value is None):
            elem.attrib['name'] = name
            elem.text = value

        return CssParameter(self, len(self._node) - 1)