code: def get_language():
      
  
      global sensor_graph, statement
  
      if sensor_graph is not None:
          return sensor_graph
  
      _create_primitives()
      _create_simple_statements()
      _create_block_bnf()
  
      sensor_graph = ZeroOrMore(statement) + StringEnd()
      sensor_graph.ignore(comment)
  
      return sensor_graph
docs: Create or retrieve the parse tree for defining a sensor graph.