<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def as_list(self, fs_type=None):
 """List mount entries"""

        entries = self._entries
        if fs_type:
            entries = filter(lambda a: a.fs_type == fs_type, entries)
        return entries