code: def input(self, s):
      # Pull off the first character to see if s looks like a string
      c = s[:1]
      if not isinstance(c, StringTypes):
          raise ValueError("Expected a string")
      self.lexdata = s
      self.lexpos = 0
      self.lexlen = len(s)
  
imports: import re
  import sys
  import types
  import copy
  import os
  import inspect
label_desc: Use image node_id 5 for calling the Lexer obj's underlying member method code with example usage: obj.input(s) without return types