def __get_chat_members(self, id):
                 return (ChatMembers
                         .select(Users)
                         .join(Users, on=(Users.id == ChatMembers.user_id))
                         .where(ChatMembers.chat_id == id))

            for member in self.__get_chat_members(1):
                print(member.username)

class ChatMembers(Model):
class Meta:
    db_table = 'chat_members'

id = BigIntegerField(index=True, unique=True)
chat_id = BigIntegerField()
user_id = BigIntegerField()

class Users(Model):
id = BigIntegerField(index=True, unique=True)
username = CharField(unique=True)
password = CharField()
phone = CharField(unique=True)