Check whether there is a blank line before epytext.

        @param node_type: type of node
        @param node: current node of pylint
        @param linenoDocstring: linenumber of docstring

def _checkBlankLineBeforeEpytext(self, node_type, node, linenoDocstring):
        """
        Check whether there is a blank line before epytext.

        @param node_type: type of node
        @param node: current node of pylint
        @param linenoDocstring: linenumber of docstring
        """
        # Check whether there is a blank line before epytext markups.
        patternEpytext = (r"\n *@(param|type|return|returns|rtype|ivar|cvar"
                          r"|raises|raise)"
                          r"\s*[a-zA-Z0-9_]*\s*\:")
        matchedEpytext = re.search(patternEpytext, node.doc)
        if matchedEpytext:
            # This docstring have epytext markups,
            # then check the blank line before them.
            posEpytext = matchedEpytext.start() + 1
            if not re.search(r"\n\s*\n\s*$", node.doc[:posEpytext]):
                self.add_message('W9207', line=linenoDocstring, node=node)