<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def SetCacheMode(mode):
 """Set the Configure cache mode. mode must be one of "auto", "force", or "cache"."""

    global cache_mode
    if mode == "auto":
        cache_mode = AUTO
    elif mode == "force":
        cache_mode = FORCE
    elif mode == "cache":
        cache_mode = CACHE
    else:
        raise ValueError("SCons.SConf.SetCacheMode: Unknown mode " + mode)