<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _hash(self, hash_name):
 """ Returns a hash object for the file at the current path. `hash_name` should be a hash algo name (such as ``'md5'`` or ``'sha1'``) that's available in the :mod:`hashlib` module. """

        m = hashlib.new(hash_name)
        for chunk in self.chunks(8192, mode="rb"):
            m.update(chunk)
        return m