code: def t_IDENTIFIER(self, t):
          r'[a-zA-Z_](\.[a-zA-Z_0-9]|[a-zA-Z_0-9])*'
  
          if t.value in THRIFT_KEYWORDS:
              # Not an identifier after all.
              t.type = t.value.upper()
  
          return f t_IDENTIFIER(self, t):
          r'[a-zA-Z_](\.[a-zA-Z_0-9]|[a-zA-Z_0-9])*'
  
          if t.value in THRIFT_KEYWORDS:
              # Not an identifier after all.
              t.type = t.value.upper()
  
          return t
docs: r'[a-zA-Z_](\.[a-zA-Z_0-9]|[a-zA-Z_0-9])*