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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 find_python(finder, line=None):
 """ Given a `pythonfinder.Finder` instance and an optional line, find a corresponding python :param finder: A :class:`pythonfinder.Finder` instance to use for searching :type finder: :class:pythonfinder.Finder` :param str line: A version, path, name, or nothing, defaults to None :return: A path to python :rtype: str """


    if line and not isinstance(line, six.string_types):
        raise TypeError(
            "Invalid python search type: expected string, received {0!r}".format(line)
        )
    if line and os.path.isabs(line):
        if os.name == "nt":
            line = posixpath.join(*line.split(os.path.sep))
        return line
    if not finder:
        from pipenv.vendor.pythonfinder import Finder
        finder = Finder(global_search=True)
    if not line:
        result = next(iter(finder.find_all_python_versions()), None)
    elif line and line[0].isdigit() or re.match(r'[\d\.]+', line):
        result = finder.find_python_version(line)
    else:
        result = finder.find_python_version(name=line)
    if not result:
        result = finder.which(line)
    if not result and not line.startswith("python"):
        line = "python{0}".format(line)
        result = find_python(finder, line)
    if not result:
        result = next(iter(finder.find_all_python_versions()), None)
    if result:
        if not isinstance(result, six.string_types):
            return result.path.as_posix()
        return result
    return