66             anchor = event.anchor
67             if anchor not in self.anchors:
69                         % anchor, event.start_mark)
70             return self.anchors[anchor]
72         anchor = event.anchor
73         if anchor is not None:
74             if anchor in self.anchors:
75                 raise ComposerError("found duplicate anchor %r; first occurrence"
76                         % anchor, self.anchors[anchor].start_mark,
80             node = self.compose_scalar_node(anchor)
82             node = self.compose_sequence_node(anchor)
84             node = self.compose_mapping_node(anchor)
88     def compose_scalar_node(self, anchor):  argument
95         if anchor is not None:
96             self.anchors[anchor] = node
99     def compose_sequence_node(self, anchor):  argument
107         if anchor is not None:
108             self.anchors[anchor] = node
117     def compose_mapping_node(self, anchor):  argument
125         if anchor is not None:
126             self.anchors[anchor] = node