handle an incoming mavlink packet

def handle_mavlink_packet(self, master, m):
        '''handle an incoming mavlink packet'''
        if m.get_type() == 'PARAM_VALUE':
            value = self.handle_px4_param_value(m)
            param_id = "%.16s" % m.param_id
            # Note: the xml specifies param_index is a uint16, so -1 in that field will show as 65535
            # We accept both -1 and 65535 as 'unknown index' to future proof us against someday having that
            # xml fixed.
            if self.fetch_set is not None:
                self.fetch_set.discard(m.param_index)
            if m.param_index != -1 and m.param_index != 65535 and m.param_index not in self.mav_param_set:
                added_new_parameter = True
                self.mav_param_set.add(m.param_index)
            else:
                added_new_parameter = False
            if m.param_count != -1:
                self.mav_param_count = m.param_count
            self.mav_param[str(param_id)] = value
            if param_id in self.fetch_one and self.fetch_one[param_id] > 0:
                self.fetch_one[param_id] -= 1
                if isinstance(value, float):
                    print("%s = %.7f" % (param_id, value))
                else:
                    print("%s = %s" % (param_id, str(value)))
            if added_new_parameter and len(self.mav_param_set) == m.param_count:
                print("Received %u parameters" % m.param_count)
                if self.logdir is not None:
                    self.mav_param.save(os.path.join(self.logdir, self.parm_file), '*', verbose=True)
                self.fetch_set = None
            if self.fetch_set is not None and len(self.fetch_set) == 0:
                self.fetch_check(master, force=True)
        elif m.get_type() == 'HEARTBEAT':
            if m.get_srcComponent() == 1:
                # remember autopilot types so we can handle PX4 parameters
                self.autopilot_type_by_sysid[m.get_srcSystem()] = m.autopilot