code: def _unescape(v):
      """Unescape characters in a TOML string."""
      i = 0
      backslash = False
      while i < len(v):
          if backslash:
              backslash = False
              if v[i] in _escapes:
                  v = (
                      v[: i - 1]
                      + _escape_to_escapedchars[v[i]]
                      + v[i + 1 :]
                  )
              elif v[i] == "\\":
                  v = v[: i - 1] + v[i:]
              elif v[i] == "u" or v[i] == "U":
                  i += 1
              else:
                  raise ValueError("Reserved escape sequence used")
              continue
          elif v[i] == "\\":
              backslash = True
          i += 1
      return v
  
imports: import datetime
  import io
  from os import linesep
  import re
  import sys
  from toml.tz import TomlTz
label_desc: Use image node_id 9 for calling a global function with example usage: _unescape(v) and returns: v