class_docstr: Exception for operations that require some engines, but none exist
code: def __str__(self):
      return (
          "This operation requires engines."
          " Try client.wait_for_engines(n) to wait for engines to register."
      )
  
imports: import builtins
  import sys
  import traceback
label_desc: Use image node_id 1 for calling the NoEnginesRegistered obj's underlying member method code with example usage: obj.__str__() and returns: str