config = {
    'required': 'Field :attr is required.',
    'boolean': 'Field :attr must be boolean.',
    'integer': 'Field :attr must be integer.',
    'string': 'Field :attr must be a string.',
    'min': 'Minimal value for :attr is :min.',
    'max': 'Maximal value for :attr is :max.',
    'in': 'Your value :value must be in list (:in)',
    'unique': ':attr already has been taken.',
    'email': 'Invalid email format ":value"',
    'attrs': {
        'first_name': 'first name',
        'email': 'Email'
    }
}