TimestampField for DRF with proper validation error and drf-spectacular docs

gistfile1.txt

from drf_spectacular.types import OpenApiTypes
from drf_spectacular.utils import extend_schema_field

@extend_schema_field(OpenApiTypes.INT)
class TimestampField(serializers.DateTimeField):
    def to_internal_value(self, value):
        try:
            return datetime.fromtimestamp(int(value), tz=pytz.UTC)
        except ValueError:
            raise exceptions.ValidationError(
                'Wrong datetime format. Use integer timestamp.'
            )

    def to_representation(self, value):
        return int(value.timestamp())