code: def _get_symbol(i):
      """Finds the i-th ASCII symbol. Works for lowercase and uppercase letters, allowing i up to
      51."""
      if i >= len(string.ascii_letters):
          raise ValueError(
              "Set the use_opt_einsum argument to True when applying more than "
              f"{len(string.ascii_letters)} wire cuts to a circuit"
          )
      return string.ascii_letters[i]
  
file_path: pennylane/pennylane/qcut/processing.py
imports: import string
  from typing import List, Sequence
  from networkx import MultiDiGraph
  import pennylane
  from pennylane import numpy
  from .utils import MeasureNode, PrepareNode
label_desc: Use image node_id 5 for calling a global function with example usage: _get_symbol(i) and returns: string