from marshmallow import Schema, fields
from marshmallow_validators.wtforms import from_wtforms
from wtforms.validators import Email, Length

# Leverage WTForms il8n
locales = ['de_DE', 'de']

class UserSchema(Schema):
    email = fields.Str(
        validate=from_wtforms([Email()], locales=locales)
    )
    password = fields.Str(
        validate=from_wtforms([Length(min=8, max=300)], locales=locales)
    )

UserSchema().validate({'email': 'invalid', 'password': 'abc'})
# {'email': ['Ungültige Email-Adresse.'],
# 'password': ['Feld muss zwischen 8 und 300 Zeichen beinhalten.']}