def childSearchPreauth(self, *paths):
        """
        Return my first existing child with a name in C{paths}.

        C{paths} is expected to be a list of *pre-secured* path fragments;
        in most cases this will be specified by a system administrator and not
        an arbitrary user.

        If no appropriately-named children exist, this will return L{None}.

        @return: L{None} or the child path.
        @rtype: L{None} or L{FilePath}
        """
        for child in paths:
            p = self._getPathAsSameTypeAs(child)
            jp = joinpath(p, child)
            if exists(jp):
                return self.clonePath(jp)

        Return my first existing child with a name in C{paths}.

        C{paths} is expected to be a list of *pre-secured* path fragments;
        in most cases this will be specified by a system administrator and not
        an arbitrary user.

        If no appropriately-named children exist, this will return L{None}.

        @return: L{None} or the child path.
        @rtype: L{None} or L{FilePath}
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/python/filepath.py