'Add new annotations to edges in the statement dependence graph.
:param list edges_to_annotate:      A list of edges to annotate.
:param new_labels:  New labels to be added to those edges.
:returns: None'

def _stmt_graph_annotate_edges(self, edges_to_annotate, **new_labels):

    graph = self.graph
    for (src, dst) in edges_to_annotate:
        if (src not in graph):
            continue
        if (dst not in graph[src]):
            continue
        data = graph[src][dst]
        for (k, v) in new_labels.iteritems():
            if (k in data):
                data[k] = (data[k] + (v,))
            else:
                data[k] = (v,)
