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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def check_issues(issues, after=None):
 """Checks issues for BEP 1 compliance."""

    issues = closed_issues(issues, after) if after else all_issues(issues)
    issues = sorted(issues, key=ISSUES_SORT_KEY)

    have_warnings = False

    for section, issue_group in groupby(issues, key=ISSUES_BY_SECTION):
        for issue in issue_group:
            have_warnings |= check_issue(issue, after)

    return have_warnings