def getValue():
    """Return a node-type specific value.

        For node type:    Return:
        'AND'             a list of parse trees
        'OR'              a list of parse trees
        'NOT'             a parse tree
        'ATOM'            a string (representing a single search term)
        'PHRASE'          a string (representing a search phrase)
        'GLOB'            a string (representing a pattern, e.g. "foo*")
        """
