def check_pattern_startswith_slash(pattern):
    regex_pattern = pattern.regex.pattern
    if regex_pattern.startswith('/') or regex_pattern.startswith('^/'):
        warning = Warning(
            "Your URL pattern {} has a regex beginning with a '/'. "
            "Remove this slash as it is unnecessary.".format(describe_pattern(pattern)),
            id="urls.W002",
        )
        return [warning]
    else:
        return []
Sorts the choices by applying order_by_count if applicable.
dataset/ETHPy150Open django/django/django/core/checks/urls.py/check_pattern_startswith_slash--crossover with--dataset/ETHPy150Open ionelmc/django-easyfilters/src/django_easyfilters/filters.py/Filter.sort_choices