<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def get_subpath(self, subpath: str):
 """Search a file or directory relative to the base path"""

        for d in self._path:
            if os.path.exists(os.path.join(d, subpath)):
                return os.path.join(d, subpath)
        raise FileNotFoundError