def getChildWithDefault(name, request):
        """
        Return a child with the given name for the given request.
        This is the external interface used by the Resource publishing
        machinery. If implementing IResource without subclassing
        Resource, it must be provided. However, if subclassing Resource,
        getChild overridden instead.

        @param name: A single path component from a requested URL.  For example,
            a request for I{http://example.com/foo/bar} will result in calls to
            this method with C{b"foo"} and C{b"bar"} as values for this
            argument.
        @type name: C{bytes}

        @param request: A representation of all of the information about the
            request that is being made for this child.
        @type request: L{twisted.web.server.Request}
        """

        Return a child with the given name for the given request.
        This is the external interface used by the Resource publishing
        machinery. If implementing IResource without subclassing
        Resource, it must be provided. However, if subclassing Resource,
        getChild overridden instead.

        @param name: A single path component from a requested URL.  For example,
            a request for I{http://example.com/foo/bar} will result in calls to
            this method with C{b"foo"} and C{b"bar"} as values for this
            argument.
        @type name: C{bytes}

        @param request: A representation of all of the information about the
            request that is being made for this child.
        @type request: L{twisted.web.server.Request}
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/web/resource.py