<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def register_module_for_export(module, export_name):
 """Register a Module to be exported under `export_name`. This function registers `module` to be exported by `LatestModuleExporter` under a subdirectory named `export_name`. Note that `export_name` must be unique for each module exported from the current graph. It only controls the export subdirectory name and it has no scope effects such as the `name` parameter during Module instantiation. Args: module: Module instance to be exported. export_name: subdirectory name to use when performing the export. Raises: ValueError: if `export_name` is already taken in the current graph. """

  for used_name, _ in tf_v1.get_collection(_EXPORT_MODULES_COLLECTION):
    if used_name == export_name:
      raise ValueError(
          "There is already a module registered to be exported as %r"
          % export_name)
  tf_v1.add_to_collection(_EXPORT_MODULES_COLLECTION, (export_name, module))