lex: state name 1 must be a string
lex: No rules defined for state 'example'
Traceback (most recent call last):
  File "./lex_state3.py", line 40, in <module>
    lex.lex()
  File "../ply/lex.py", line 759, in lex
    raise SyntaxError,"lex: Unable to build lexer."
SyntaxError: lex: Unable to build lexer.