code: def _get_backends(group, *, load_and_call=False):
      items = entry_points(group=group)
      rv = {}
      for ep in items:
          if ep.name in rv:
              warnings.warn(
                  f"networkx backend defined more than once: {ep.name}",
                  RuntimeWarning,
                  stacklevel=2,
              )
          elif load_and_call:
              try:
                  rv[ep.name] = ep.load()()
              except Exception as exc:
                  warnings.warn(
                      f"Error encountered when loading info for backend {ep.name}: {exc}",
                      RuntimeWarning,
                      stacklevel=2,
                  )
          else:
              rv[ep.name] = ep
      # nx-loopback backend is only available when testing (added in conftest.py)
      rv.pop("nx-loopback", None)
      return rv
  
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 1 for calling a global function with example usage: _get_backends(group) and returns: rv