def __add__(self, other):
        if self.type != other.type:
            raise TypeError("Different types of operandi is not allowed.")
        if self.is_number():
            self_value = float(self.value) if "." in self.value else int(self.value)
            other_value = float(other.value) if "." in other.value else int(other.value)
            return DynamoType(
                {DDBType.NUMBER: "{v}".format(v=self_value + other_value)}
            )
        else:
            raise IncorrectDataType()