minor: some documentation

interp/baker/__init__.py

@@ -205,6 +205,10 @@ def _samples_ur(items, k, offset = 0):
     yield tuple([x + offset  for sel in selections for x in sel])
 
 def memoize(f):
+  """
+    I only cache on power and phicount; I figure that one should stick to a
+    particular offset throughout one's codebase.
+  """
   cache = {}
   def memf(*x, **kargs):
     if x not in cache: