How to use the requests3.core._http.base.DEFAULT_PORTS.get function in requests3

"""
        Get a :class:`ConnectionPool` based on the host, port, and scheme.

        If ``port`` isn't given, it will be derived from the ``scheme`` using
        ``urllib3.connectionpool.port_by_scheme``. If ``pool_kwargs`` is
        provided, it is merged with the instance's ``connection_pool_kw``
        variable and used to create the new connection pool, if one is
        needed.
        """
        if not host:
            raise LocationValueError("No host specified.")

        request_context = self._merge_pool_kwargs(pool_kwargs)
        request_context['scheme'] = scheme or 'http'
        if not port:
            port = DEFAULT_PORTS.get(request_context['scheme'].lower(), 80)
        request_context['port'] = port
        request_context['host'] = host
        return self.connection_from_context(request_context)

"""
        Get a :class:`ConnectionPool` based on the host, port, and scheme.

        If ``port`` isn't given, it will be derived from the ``scheme`` using
        ``urllib3.connectionpool.port_by_scheme``. If ``pool_kwargs`` is
        provided, it is merged with the instance's ``connection_pool_kw``
        variable and used to create the new connection pool, if one is
        needed.
        """
        if not host:
            raise LocationValueError("No host specified.")

        request_context = self._merge_pool_kwargs(pool_kwargs)
        request_context['scheme'] = scheme or 'http'
        if not port:
            port = DEFAULT_PORTS.get(request_context['scheme'].lower(), 80)
        request_context['port'] = port
        request_context['host'] = host
        return self.connection_from_context(request_context)

def __init__(
        self,
        proxy_url,
        num_pools=10,
        headers=None,
        proxy_headers=None,
        **connection_pool_kw
    ):
        if isinstance(proxy_url, HTTPConnectionPool):
            proxy_url = '%s://%s:%i' % (
                proxy_url.scheme, proxy_url.host, proxy_url.port
            )
        proxy = parse_url(proxy_url)
        if not proxy.port:
            port = DEFAULT_PORTS.get(proxy.scheme, 80)
            proxy = proxy._replace(port=port)
        if proxy.scheme not in ("http", "https"):
            raise ProxySchemeUnknown(proxy.scheme)

        self.proxy = proxy
        self.proxy_headers = proxy_headers or {}
        connection_pool_kw['_proxy'] = self.proxy
        connection_pool_kw['_proxy_headers'] = self.proxy_headers
        super(ProxyManager, self).__init__(
            num_pools, headers, **connection_pool_kw
        )

:param url:
        Absolute URL string that must include the scheme. Port is optional.

    :param \\**kw:
        Passes additional parameters to the constructor of the appropriate
        :class:`.ConnectionPool`. Useful for specifying things like
        timeout, maxsize, headers, etc.

    Example::

        >>> conn = connection_from_url('http://google.com/')
        >>> r = conn.request('GET', '/')
    """
    scheme, host, port = get_host(url)
    port = port or DEFAULT_PORTS.get(scheme, 80)
    if scheme == 'https':
        return HTTPSConnectionPool(host, port=port, **kw)

    else:
        return HTTPConnectionPool(host, port=port, **kw)

:param url:
        Absolute URL string that must include the scheme. Port is optional.

    :param \\**kw:
        Passes additional parameters to the constructor of the appropriate
        :class:`.ConnectionPool`. Useful for specifying things like
        timeout, maxsize, headers, etc.

    Example::

        >>> conn = connection_from_url('http://google.com/')
        >>> r = conn.request('GET', '/')
    """
    scheme, host, port = get_host(url)
    port = port or DEFAULT_PORTS.get(scheme, 80)
    if scheme == 'https':
        return HTTPSConnectionPool(host, port=port, **kw)

    else:
        return HTTPConnectionPool(host, port=port, **kw)

def __init__(
        self,
        proxy_url,
        num_pools=10,
        headers=None,
        proxy_headers=None,
        **connection_pool_kw
    ):
        if isinstance(proxy_url, HTTPConnectionPool):
            proxy_url = '%s://%s:%i' % (
                proxy_url.scheme, proxy_url.host, proxy_url.port
            )
        proxy = parse_url(proxy_url)
        if not proxy.port:
            port = DEFAULT_PORTS.get(proxy.scheme, 80)
            proxy = proxy._replace(port=port)
        if proxy.scheme not in ("http", "https"):
            raise ProxySchemeUnknown(proxy.scheme)

        self.proxy = proxy
        self.proxy_headers = proxy_headers or {}
        connection_pool_kw['_proxy'] = self.proxy
        connection_pool_kw['_proxy_headers'] = self.proxy_headers
        super(ProxyManager, self).__init__(
            num_pools, headers, **connection_pool_kw
        )