class_docstr: A set of magics useful when controlling a parallel IPython cluster.
code: def _eval_signal_str(self, sig_str: str):
      if sig_str.isdigit():
          return int(sig_str)
      return sig_str
  
imports: import time
  from contextlib import contextmanager
  import inspect
  import re
  import sys
  from textwrap import dedent
  from IPython.core import magic_arguments
  from IPython.core.error import UsageError
  from IPython.core.magic import Magics, no_var_expand
  import ipyparallel
  from ..None import error
label_desc: Use image node_id 3 for calling the ParallelMagics obj's underlying member method code with example usage: obj._eval_signal_str(sig_str) and returns: sig_str, int