code: def create(cls, env, filenames, trim=False):
          
          import_graph = cls(env)
          for filename in filenames:
              import_graph.add_file_recursive(os.path.abspath(filename), trim)
          import_graph.build()
          return import_graph
docs: Create and return a final graph.
  
          Args:
            env: An environment.Environment object
            filenames: A list of filenames
            trim: Whether to trim the dependencies of builtin and system files.
  
          Returns:
            An immutable ImportGraph with the recursive dependencies of all the
            files in filenames