_python2.py 文件源码

def _pl_find_on_path(self, fullname, path=None):
        subname = fullname.split(".")[-1]
        if self.path is None and subname != fullname:
            return None

        path = os.path.realpath(self.path)
        for (fp, ispkg) in FLS:
            for loader in self._loader_handlers:
                composed_path = fp % (('%s' + SEP + '%s') % (path, subname), loader.suffix)
                if os.path.isdir(composed_path):
                    raise IOError("Invalid: Directory name ends in recognized suffix")
                if os.path.isfile(composed_path):
                    return PolyLoader(fullname, composed_path, ispkg)

        # Fall back onto Python's own methods.
        try:
            file, filename, etc = imp.find_module(subname, [path])
        except ImportError as e:
            return None
        return pkgutil.ImpLoader(fullname, file, filename, etc)