name 'dataclass' is not defined

This error message indicates that the Python module "dataclass" is not imported or installed in the current environment.

Data classes were introduced in Python 3.7 and are used to define classes that are primarily intended to store data. To use data classes, you need to import the module "dataclasses" and use the decorator "@dataclass" to define your class.

Here is an example of how to define a simple data class:

from dataclasses import dataclass

@dataclass
class Person:
    name: str
    age: int
    gender: str

Make sure that you have installed the latest version of Python and the "dataclasses" module. You can install the module via pip, by running the following command in your terminal:

pip install dataclasses