code: def custom_operation(dbg, thread_id, frame_id, scope, attrs, style, code_or_file, operation_fn_name):
      
      expressionValue = getVariable(dbg, thread_id, frame_id, scope, attrs)
  
      try:
          namespace = {'__name__': '<custom_operation>'}
          if style == "EXECFILE":
              namespace['__file__'] = code_or_file
              execfile(code_or_file, namespace, namespace)
          else:  # style == EXEC
              namespace['__file__'] = '<customOperationCode>'
              Exec(code_or_file, namespace, namespace)
  
          return str(namespace[operation_fn_name](expressionValue))
      except:
          pydev_log.exception()
docs: We'll execute the code_or_file and then search in the namespace the operation_fn_name to execute with the given var.
  
      code_or_file: either some code (i.e.: from pprint import pprint) or a file to be executed.
      operation_fn_name: the name of the operation to execute after the exec (i.e.: pprint)