<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def description(self, platform, key):
 """Return the patter description."""

        patterns = self._dict_dscr.get(platform, None)
        description = patterns.get(key, None)
        return description