code: def source_node_type(self) -> str:
      return self.__source_node_type
  
file_path: AutoGL/autogl/data/graph/_general_static_graph/_canonical_edge_type.py
imports: import typing
label_desc: Use image node_id 2 for calling the CanonicalEdgeType obj's underlying member method code with example usage: obj.source_node_type() and returns: self