diff --git a/parso/pgen2/grammar.py b/parso/pgen2/grammar.py
index f48c757..1a2c6e9 100644
--- a/parso/pgen2/grammar.py
+++ b/parso/pgen2/grammar.py
@@ -16,11 +16,6 @@ fallback token code OP, but the parser needs the actual token code.
 
 """
 
-try:
-    import cPickle as pickle
-except:
-    import pickle
-
 
 class Grammar(object):
     """Pgen parsing tables conversion class.
diff --git a/parso/pgen2/pgen.py b/parso/pgen2/pgen.py
index b95454b..abfad0a 100644
--- a/parso/pgen2/pgen.py
+++ b/parso/pgen2/pgen.py
@@ -204,6 +204,9 @@ def _simplify_dfas(dfas):
 
 
 def _make_dfas(start, finish):
+    """
+    This is basically doing what the powerset construction algorithm is doing.
+    """
     # To turn an NFA into a DFA, we define the states of the DFA
     # to correspond to *sets* of states of the NFA.  Then do some
     # state reduction.