code: def backend(name="jax"):
      """Returns the backend used to provide fastmath ops ('tf' or 'jax')."""
      if override_backend:
          return _get_backend_from_string(override_backend)
  
      if default_backend:
          return _get_backend_from_string(default_backend)
  
      if isinstance(name, Backend):
          return _backend_dict[name]
  
      # name is a string.
      return _get_backend_from_string(name)
  
imports: import contextlib
  import enum
  import gin
  from trax.fastmath.jax import JAX_BACKEND
  from trax.fastmath.numpy import NUMPY_BACKEND
  from trax.fastmath.tf import TF_BACKEND
label_desc: Use image node_id 43 for calling a global function with example usage: backend(name) and returns: _get_backend_from_string, _get_backend_from_string, _get_backend_from_string, _backend_dict