How to use the conda.common.url.join_url function in conda

subname = test_url.replace(join_url(location, name), '', 1).strip('/')
            channel_name = join_url(name, subname)
            channel = _get_channel_for_name(channel_name)
            return channel.location, channel_name, channel.scheme, channel.auth, channel.token

    # Step 3. migrated_channel_aliases matches
    for migrated_alias in context.migrated_channel_aliases:
        if test_url.startswith(migrated_alias.location):
            name = test_url.replace(migrated_alias.location, '', 1).strip('/')
            ca = context.channel_alias
            return ca.location, name, ca.scheme, ca.auth, ca.token

    # Step 4. custom_channels matches
    for name, channel in sorted(context.custom_channels.items(), reverse=True,
                                key=lambda x: len(x[0])):
        that_test_url = join_url(channel.location, channel.name)
        if tokenized_startswith(test_url.split('/'), that_test_url.split('/')):
            subname = test_url.replace(that_test_url, '', 1).strip('/')
            return (channel.location, join_url(channel.name, subname), scheme,
                    channel.auth, channel.token)

    # Step 5. channel_alias match
    ca = context.channel_alias
    if ca.location and tokenized_startswith(test_url.split('/'), ca.location.split('/')):
        name = test_url.replace(ca.location, '', 1).strip('/') or None
        return ca.location, name, scheme, ca.auth, ca.token

    # Step 6. not-otherwise-specified file://-type urls
    if host is None:
        # this should probably only happen with a file:// type url
        assert port is None
        location, name = test_url.rsplit('/', 1)

return channel.location, channel_name, channel.scheme, channel.auth, channel.token

    # Step 3. migrated_channel_aliases matches
    for migrated_alias in context.migrated_channel_aliases:
        if test_url.startswith(migrated_alias.location):
            name = test_url.replace(migrated_alias.location, '', 1).strip('/')
            ca = context.channel_alias
            return ca.location, name, ca.scheme, ca.auth, ca.token

    # Step 4. custom_channels matches
    for name, channel in sorted(context.custom_channels.items(), reverse=True,
                                key=lambda x: len(x[0])):
        that_test_url = join_url(channel.location, channel.name)
        if tokenized_startswith(test_url.split('/'), that_test_url.split('/')):
            subname = test_url.replace(that_test_url, '', 1).strip('/')
            return (channel.location, join_url(channel.name, subname), scheme,
                    channel.auth, channel.token)

    # Step 5. channel_alias match
    ca = context.channel_alias
    if ca.location and tokenized_startswith(test_url.split('/'), ca.location.split('/')):
        name = test_url.replace(ca.location, '', 1).strip('/') or None
        return ca.location, name, scheme, ca.auth, ca.token

    # Step 6. not-otherwise-specified file://-type urls
    if host is None:
        # this should probably only happen with a file:// type url
        assert port is None
        location, name = test_url.rsplit('/', 1)
        if not location:
            location = '/'
        _scheme, _auth, _token = 'file', None, None

def test_bare_channel_file(self):
        url = "file:///conda-01"
        channel = Channel(url)
        assert channel.scheme == "file"
        assert channel.location == "/"
        assert channel.platform is None
        assert channel.canonical_name == url
        assert channel.name == "conda-01"

        assert channel.base_url == url
        assert channel.url() == join_url(url, context.subdir)
        assert channel.urls() == [
            join_url(url, context.subdir),
            join_url(url, 'noarch'),
        ]

path = path and path.rstrip('/')
    test_url = Url(host=host, port=port, path=path).url

    # Step 1. No path given; channel name is None
    if not path:
        return Url(host=host, port=port).url.rstrip('/'), None, scheme or None, None, None

    # Step 2. migrated_custom_channels matches
    for name, location in sorted(context.migrated_custom_channels.items(), reverse=True,
                                 key=lambda x: len(x[0])):
        location, _scheme, _auth, _token = split_scheme_auth_token(location)
        if tokenized_conda_url_startswith(test_url, join_url(location, name)):
            # translate location to new location, with new credentials
            subname = test_url.replace(join_url(location, name), '', 1).strip('/')
            channel_name = join_url(name, subname)
            channel = _get_channel_for_name(channel_name)
            return channel.location, channel_name, channel.scheme, channel.auth, channel.token

    # Step 3. migrated_channel_aliases matches
    for migrated_alias in context.migrated_channel_aliases:
        if test_url.startswith(migrated_alias.location):
            name = test_url.replace(migrated_alias.location, '', 1).strip('/')
            ca = context.channel_alias
            return ca.location, name, ca.scheme, ca.auth, ca.token

    # Step 4. custom_channels matches
    for name, channel in sorted(context.custom_channels.items(), reverse=True,
                                key=lambda x: len(x[0])):
        that_test_url = join_url(channel.location, channel.name)
        if tokenized_startswith(test_url.split('/'), that_test_url.split('/')):
            subname = test_url.replace(that_test_url, '', 1).strip('/')

}

        channel_url = self.url_w_credentials
        legacy_packages = json_obj.get("packages", {})
        conda_packages = json_obj.get("packages.conda", {})
        _tar_bz2 = CONDA_PACKAGE_EXTENSION_V1
        use_these_legacy_keys = set(iterkeys(legacy_packages)) - set(
            k[:-6] + _tar_bz2 for k in iterkeys(conda_packages)
        )

        for group, copy_legacy_md5 in (
                (iteritems(conda_packages), True),
                (((k, legacy_packages[k]) for k in use_these_legacy_keys), False)):
            for fn, info in group:
                info['fn'] = fn
                info['url'] = join_url(channel_url, fn)
                if copy_legacy_md5:
                    counterpart = fn.replace('.conda', '.tar.bz2')
                    if counterpart in legacy_packages:
                        info['legacy_bz2_md5'] = legacy_packages[counterpart].get('md5')
                        info['legacy_bz2_size'] = legacy_packages[counterpart].get('size')
                if (add_pip and info['name'] == 'python' and
                        info['version'].startswith(('2.', '3.'))):
                    info['depends'].append('pip')
                info.update(meta_in_common)
                if info.get('record_version', 0) > 1:
                    log.debug("Ignoring record_version %d from %s",
                              info["record_version"], info['url'])
                    continue
                package_record = PackageRecord(**info)

                _package_records.append(package_record)

The remote server could not find the noarch directory for the
                    requested channel with url: %s

                    As of conda 4.3, a valid channel must contain a `noarch/repodata.json` and
                    associated `noarch/repodata.json.bz2` file, even if `noarch/repodata.json` is
                    empty. please request that the channel administrator create
                    `noarch/repodata.json` and associated `noarch/repodata.json.bz2` files.
                    $ mkdir noarch
                    $ echo '{}' > noarch/repodata.json
                    $ bzip2 -k noarch/repodata.json

                    You will need to adjust your conda configuration to proceed.
                    Use `conda config --show` to view your configuration's current state.
                    Further configuration help can be found at <%s>.
                    """) % (maybe_unquote(dirname(url)),
                            join_url(CONDA_HOMEPAGE_URL, 'docs/config.html'))

        elif status_code == 401:
            channel = Channel(url)
            if channel.token:
                help_message = dals("""
                The token '%s' given for the URL is invalid.

                If this token was pulled from anaconda-client, you will need to use
                anaconda-client to reauthenticate.

                If you supplied this token to conda directly, you will need to adjust your
                conda configuration to proceed.

                Use `conda config --show` to view your configuration's current state.
                Further configuration help can be found at <%s>.
               """) % (channel.token, join_url(CONDA_HOMEPAGE_URL, 'docs/config.html'))

if etag:
        headers["If-None-Match"] = etag
    if mod_stamp:
        headers["If-Modified-Since"] = mod_stamp

    if 'repo.continuum.io' in url or url.startswith("file://"):
        filename = 'repodata.json.bz2'
        headers['Accept-Encoding'] = 'identity'
    else:
        headers['Accept-Encoding'] = 'gzip, deflate, compress, identity'
        headers['Content-Type'] = 'application/json'
        filename = 'repodata.json'

    try:
        timeout = context.remote_connect_timeout_secs, context.remote_read_timeout_secs
        resp = session.get(join_url(url, filename), headers=headers, proxies=session.proxies,
                           timeout=timeout)
        if log.isEnabledFor(DEBUG):
            log.debug(stringify(resp))
        resp.raise_for_status()

        if resp.status_code == 304:
            raise Response304ContentUnchanged()

        def maybe_decompress(filename, resp_content):
            return ensure_text_type(bz2.decompress(resp_content)
                                    if filename.endswith('.bz2')
                                    else resp_content).strip()
        json_str = maybe_decompress(filename, resp.content)
        fetched_repodata = json.loads(json_str) if json_str else {}
        fetched_repodata['_url'] = url
        add_http_value_to_dict(resp, 'Etag', fetched_repodata, '_etag')

The remote server could not find the noarch directory for the
                    requested channel with url: %s

                    As of conda 4.3, a valid channel must contain a `noarch/repodata.json` and
                    associated `noarch/repodata.json.bz2` file, even if `noarch/repodata.json` is
                    empty. please request that the channel administrator create
                    `noarch/repodata.json` and associated `noarch/repodata.json.bz2` files.
                    $ mkdir noarch
                    $ echo '{}' > noarch/repodata.json
                    $ bzip2 -k noarch/repodata.json

                    You will need to adjust your conda configuration to proceed.
                    Use `conda config --show` to view your configuration's current state.
                    Further configuration help can be found at <%s>.
                    """) % (maybe_unquote(dirname(url)),
                            join_url(CONDA_HOMEPAGE_URL, 'docs/config.html'))

        elif status_code == 403:
            if not url.endswith('/noarch'):
                return None
            else:
                if context.allow_non_channel_urls:
                    help_message = dedent("""
                    WARNING: The remote server could not find the noarch directory for the
                    requested channel with url: %s

                    It is possible you have given conda an invalid channel. Please double-check
                    your conda configuration using `conda config --show`.

                    If the requested url is in fact a valid conda channel, please request that the
                    channel administrator create `noarch/repodata.json` and associated
                    `noarch/repodata.json.bz2` files, even if `noarch/repodata.json` is empty.

def urls(self, with_credentials=False, subdirs=None):
        if subdirs is None:
            subdirs = context.subdirs

        assert isiterable(subdirs), subdirs  # subdirs must be a non-string iterable

        if self.canonical_name == UNKNOWN_CHANNEL:
            return Channel(DEFAULTS_CHANNEL_NAME).urls(with_credentials, subdirs)

        base = [self.location]
        if with_credentials and self.token:
            base.extend(['t', self.token])
        base.append(self.name)
        base = join_url(*base)

        def _platforms():
            if self.platform:
                yield self.platform
                if self.platform != 'noarch':
                    yield 'noarch'
            else:
                for subdir in subdirs:
                    yield subdir

        bases = (join_url(base, p) for p in _platforms())

        if with_credentials and self.auth:
            return ["%s://%s@%s" % (self.scheme, self.auth, b) for b in bases]
        else:
            return ["%s://%s" % (self.scheme, b) for b in bases]

session = CondaSession()

    headers = {}
    if etag:
        headers["If-None-Match"] = etag
    if mod_stamp:
        headers["If-Modified-Since"] = mod_stamp

    headers['Accept-Encoding'] = 'gzip, deflate, compress, identity'
    headers['Content-Type'] = 'application/json'
    filename = repodata_fn

    try:
        timeout = context.remote_connect_timeout_secs, context.remote_read_timeout_secs
        resp = session.get(join_url(url, filename), headers=headers, proxies=session.proxies,
                           timeout=timeout)
        if log.isEnabledFor(DEBUG):
            log.debug(stringify(resp, content_max_len=256))
        resp.raise_for_status()

    except RequestsProxyError:
        raise ProxyError()   # see #3962

    except InvalidSchema as e:
        if 'SOCKS' in text_type(e):
            message = dals("""
            Requests has identified that your current working environment is configured
            to use a SOCKS proxy, but pysocks is not installed.  To proceed, remove your
            proxy configuration, run `conda install pysocks`, and then you can re-enable
            your proxy configuration.
            """)