SAN FRANCISCO (AP) — San Francisco's city attorney took legal action Thursday to stop the agency that certifies two-year colleges in the western U.S. from revoking the accreditation of the city's community college, a sanction likely to force California's largest school to close. City Attorney Dennis Herrera filed a lawsuit alleging that politics, not performance, is behind the penalty the Accrediting Commission for Community and Junior Colleges imposed on City College of San Francisco last month. The commission notified City College that it would lose its accreditation next summer for failing to meet quality assurance standards in areas such as financial management and instructional standards.