docstr: Look ahead n chars.
docstr_tok: ["Look","ahead","n","chars","."]
code: def lookahead(self, n):
      """Look ahead n chars."""
      j = self.i + n
      if j < len(self.s):
          return self.s[j]
      else:
          return ""
  
file_path: catboost/contrib/tools/cython/Cython/Plex/Traditional.py
imports: from __future__ import absolute_import
  from .Regexps import Alt, Seq, Rep, Rep1, Opt, Any, AnyBut, Bol, Eol, Char
  from .Errors import PlexError
label_desc: Use image node_id 10 for calling the REParser obj's underlying member method code with example usage: obj.lookahead(n) and returns: self, str