code: def _escape_sequence(self, char):
          
  
          num = ord(char)
          if char == "[":
              self.state = "escape-lb"
          elif char == "(":
              self.state = "charset-g0"
          elif char == ")":
              self.state = "charset-g1"
          elif num in self.escape:
              self.dispatch(self.escape[num])
              self.state = "stream"
          elif self.fail_on_unknown_esc:
              raise StreamProcessError("Unexpected character '%c' == '0x%02x'" % (char, ord(char)))
docs: Handle characters seen when in an escape sequence. Most non-vt52
          commands start with a left-bracket after the escape and then a 
          stream of parameters and a command.