def scan_setup_py():
    """Validate the contents of setup.py against Versioneer's expectations."""
    found = set()
    setters = False
    errors = 0
    with open('setup.py', 'r') as f:
        for line in f.readlines():
            if 'import versioneer' in line:
                found.add('import')
            if 'versioneer.get_cmdclass(' in line:
                found.add('cmdclass')
            if 'versioneer.get_version()' in line:
                found.add('get_version')
            if 'versioneer.VCS' in line:
                setters = True
            if 'versioneer.versionfile_source' in line:
                setters = True
    if len(found) != 3:
        print('')
        print('Your setup.py appears to be missing some important items')
        print('(but I might be wrong). Please make sure it has something')
        print('roughly like the following:')
        print('')
        print(' import versioneer')
        print(' setup( version=versioneer.get_version(),')
        print('        cmdclass=versioneer.get_cmdclass(),  ...)')
        print('')
        errors += 1
    if setters:
        print("You should remove lines like 'versioneer.VCS = ' and")
        print("'versioneer.versionfile_source = ' . This configuration")
        print('now lives in setup.cfg, and should be removed from setup.py')
        print('')
        errors += 1
    return errors
