code: def is_operation_source(source):
      cls = resolverlib.resolver_class_for_source(source)
      return cls is not None and issubclass(
          cls, resolverlib.OperationResolver
      )
  
imports: import os
  import re
  import logging
  import typing
  from guild import cli
  from guild import resolver
  from guild import resourcedef
  from guild import util
label_desc: Use image node_id 47 for calling a global function with example usage: is_operation_source(source) and returns: unknown