def options(self, parser, env):
        """
        Add options to command line.
        """
        super(Coverage, self).options(parser, env)
        parser.add_option("--cover-package", action="append",
                          default=env.get('NOSE_COVER_PACKAGE'),
                          metavar="PACKAGE",
                          dest="cover_packages",
                          help="Restrict coverage output to selected packages "
                          "[NOSE_COVER_PACKAGE]")
        parser.add_option("--cover-erase", action="store_true",
                          default=env.get('NOSE_COVER_ERASE'),
                          dest="cover_erase",
                          help="Erase previously collected coverage "
                          "statistics before run")
        parser.add_option("--cover-tests", action="store_true",
                          dest="cover_tests",
                          default=env.get('NOSE_COVER_TESTS'),
                          help="Include test modules in coverage report "
                          "[NOSE_COVER_TESTS]")
        parser.add_option("--cover-min-percentage", action="store",
                          dest="cover_min_percentage",
                          default=env.get('NOSE_COVER_MIN_PERCENTAGE'),
                          help="Minimum percentage of coverage for tests"
                          "to pass [NOSE_COVER_MIN_PERCENTAGE]")
        parser.add_option("--cover-inclusive", action="store_true",
                          dest="cover_inclusive",
                          default=env.get('NOSE_COVER_INCLUSIVE'),
                          help="Include all python files under working "
                          "directory in coverage report.  Useful for "
                          "discovering holes in test coverage if not all "
                          "files are imported by the test suite. "
                          "[NOSE_COVER_INCLUSIVE]")
        parser.add_option("--cover-html", action="store_true",
                          default=env.get('NOSE_COVER_HTML'),
                          dest='cover_html',
                          help="Produce HTML coverage information")
        parser.add_option('--cover-html-dir', action='store',
                          default=env.get('NOSE_COVER_HTML_DIR', 'cover'),
                          dest='cover_html_dir',
                          metavar='DIR',
                          help='Produce HTML coverage information in dir')
        parser.add_option("--cover-branches", action="store_true",
                          default=env.get('NOSE_COVER_BRANCHES'),
                          dest="cover_branches",
                          help="Include branch coverage in coverage report "
                          "[NOSE_COVER_BRANCHES]")
        parser.add_option("--cover-xml", action="store_true",
                          default=env.get('NOSE_COVER_XML'),
                          dest="cover_xml",
                          help="Produce XML coverage information")
        parser.add_option("--cover-xml-file", action="store",
                          default=env.get('NOSE_COVER_XML_FILE', 'coverage.xml'),
                          dest="cover_xml_file",
                          metavar="FILE",
                          help="Produce XML coverage information in file")
Add options to command line.