<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def cache_return(func):
 """Cache the return value of a function without arguments"""


    _cache = []

    def wrap():
        if not _cache:
            _cache.append(func())
        return _cache[0]
    return wrap