Example CSV row deserializer using Python dataclasses

dataclass_csv.py

import csv
from dataclasses import dataclass, fields, is_dataclass
from typing import TypeVar

@dataclass
class Widget:
    name: str
    amount: int


T = TypeVar('T')


def deserialize_csv_row(typ: type[T], row: str) -> T:
    if not is_dataclass(typ):
        raise TypeError(
            f'Cannot deserialize type from CSV row: {type(x)}'
        )
    values = []
    for cells in csv.reader([row]):
        x_fields = fields(x)
        x_fields_len = len(x_fields)
        cells_len = len(cells)
        if x_fields_len != cells_len:
            raise ValueError(
                f'Row length mismatch: type {typ} expects {x_fields_len} cells '
                f'but got {cells_len}'
            )
        for f, cell in zip(x_fields, cells):
            values.append(deserialize_csv_cell(f.type, cell))
    return typ(*values)


def deserialize_csv_cell(typ: type[T], cell: str) -> T:
    if typ is str:
        return cell
    if typ is int:
        return int(cell)
    raise TypeError(
        f'Cannot deserialize type from CSV cell: type was {type(x)}'
    )