code: def __signature__(self):
      if self._sig is None:
          sig = inspect.signature(self.orig_func)
          # `backend` is now a reserved argument used by dispatching.
          # assert "backend" not in sig.parameters
          if not any(
              p.kind == inspect.Parameter.VAR_KEYWORD
              for p in sig.parameters.values()
          ):
              sig = sig.replace(
                  parameters=[
                      *sig.parameters.values(),
                      inspect.Parameter(
                          "backend",
                          inspect.Parameter.KEYWORD_ONLY,
                          default=None,
                      ),
                      inspect.Parameter(
                          "backend_kwargs",
                          inspect.Parameter.VAR_KEYWORD,
                      ),
                  ]
              )
          else:
              *parameters, var_keyword = sig.parameters.values()
              sig = sig.replace(
                  parameters=[
                      *parameters,
                      inspect.Parameter(
                          "backend",
                          inspect.Parameter.KEYWORD_ONLY,
                          default=None,
                      ),
                      var_keyword,
                  ]
              )
          self._sig = sig
      return self._sig
  
imports: import inspect
  import os
  import sys
  import warnings
  from functools import partial
  from importlib.metadata import entry_points
  import networkx
  from ..exception import NetworkXNotImplemented
label_desc: Use image node_id 4 for calling the _dispatchable obj's underlying member method code with example usage: obj.__signature__() and returns: self