**Django 3.***
Доступные подклассы для выборки запросов типа:
"user_name__icontains"
"user_name__iregex"
"user_name__startswith"
django.db.models.query_utils :
'contained_by': <class 'django.contrib.postgres.fields.ranges.RangeContainedBy'>,
'gte': <class 'django.db.models.lookups.IntegerGreaterThanOrEqual'>,
'lt': <class 'django.db.models.lookups.IntegerLessThan'>,
'contains': <class 'django.db.models.lookups.Contains'>,
'endswith': <class 'django.db.models.lookups.EndsWith'>,
'exact': <class 'django.db.models.lookups.Exact'>,
'gt': <class 'django.db.models.lookups.GreaterThan'>,
'gte': <class 'django.db.models.lookups.GreaterThanOrEqual'>,
'icontains': <class 'django.db.models.lookups.IContains'>,
'iendswith': <class 'django.db.models.lookups.IEndsWith'>,
'iexact': <class 'django.db.models.lookups.IExact'>,
'in': <class 'django.db.models.lookups.In'>,
'iregex': <class 'django.db.models.lookups.IRegex'>,
'isnull': <class 'django.db.models.lookups.IsNull'>,
'istartswith': <class 'django.db.models.lookups.IStartsWith'>,
'lt': <class 'django.db.models.lookups.LessThan'>,
'lte': <class 'django.db.models.lookups.LessThanOrEqual'>,
'range': <class 'django.db.models.lookups.Range'>,
'regex': <class 'django.db.models.lookups.Regex'>,
'startswith': <class 'django.db.models.lookups.StartsWith'>,