def METHOD_NAME(missing, package_set):
    missing_reqs = dict()
    description = '{}Missing dependencies:\n'.format(_indent * 2)
    for pkg_name in missing:
        for result in missing[pkg_name]:
            req_name = result[0]
            if not req_name in missing_reqs:
                missing_reqs[req_name] = collect_package_requirements_by_requirement_name(req_name, package_set)
    for req_name, required_by in missing_reqs.items():
        description += '{}{}:\n'.format(_indent * 3, req_name)
        description += '{}Required by:\n'.format(_indent * 4)
        for pkg_name, specifier in required_by.items():
            description += '{}{} {} ({}: {})\n'.format(
                _indent * 5,
                pkg_name,
                package_set[pkg_name].version,
                req_name,
                specifier,
            )
    return description