diff --git a/runtime/Python2/src/antlr4/BufferedTokenStream.py b/runtime/Python2/src/antlr4/BufferedTokenStream.py
index 5f3cfda6a..fe11d2118 100644
--- a/runtime/Python2/src/antlr4/BufferedTokenStream.py
+++ b/runtime/Python2/src/antlr4/BufferedTokenStream.py
@@ -128,7 +128,6 @@ class BufferedTokenStream(TokenStream):
     # @see #get(int i)
     #/
     def sync(self, i):
-        assert i >= 0
         n = i - len(self.tokens) + 1 # how many more elements we need?
         if n > 0 :
             fetched = self.fetch(n)
diff --git a/runtime/Python2/src/antlr4/PredictionContext.py b/runtime/Python2/src/antlr4/PredictionContext.py
index af7d298b2..ba28eca7b 100644
--- a/runtime/Python2/src/antlr4/PredictionContext.py
+++ b/runtime/Python2/src/antlr4/PredictionContext.py
@@ -142,7 +142,6 @@ class SingletonPredictionContext(PredictionContext):
             return SingletonPredictionContext(parent, returnState)
 
     def __init__(self, parent, returnState):
-        assert returnState!=ATNState.INVALID_STATE_NUMBER
         hashCode = calculateHashCode(parent, returnState)
         super(SingletonPredictionContext, self).__init__(hashCode)
         self.parentCtx = parent
@@ -152,11 +151,9 @@ class SingletonPredictionContext(PredictionContext):
         return 1
 
     def getParent(self, index):
-        assert index == 0
         return self.parentCtx
 
     def getReturnState(self, index):
-        assert index == 0
         return self.returnState
 
     def __eq__(self, other):
@@ -166,8 +163,6 @@ class SingletonPredictionContext(PredictionContext):
             return False
         elif not isinstance(other, SingletonPredictionContext):
             return False
-        elif hash(self) != hash(other):
-            return False # can't be same if hash is different
         else:
             return self.returnState == other.returnState and self.parentCtx==other.parentCtx
 
@@ -212,8 +207,6 @@ class ArrayPredictionContext(PredictionContext):
 
     def __init__(self, parents, returnStates):
         super(ArrayPredictionContext, self).__init__(calculateListsHashCode(parents, returnStates))
-        assert parents is not None and len(parents)>0
-        assert returnStates is not None and len(returnStates)>0
         self.parents = parents
         self.returnStates = returnStates
 
@@ -281,17 +274,7 @@ def PredictionContextFromRuleContext(atn, outerContext=None):
     return SingletonPredictionContext.create(parent, transition.followState.stateNumber)
 
 
-def calculateListsHashCode(parents, returnStates ):
-
-    with StringIO() as s:
-        for parent in parents:
-            s.write(unicode(parent))
-        for returnState in returnStates:
-            s.write(unicode(returnState))
-        return hash(s.getvalue())
-
 def merge(a, b, rootIsWildcard, mergeCache):
-    assert a is not None and b is not None # must be empty context, never null
 
     # share same graph if both same
     if a==b:
@@ -491,9 +474,9 @@ def mergeArrays(a, b, rootIsWildcard, mergeCache):
             return previous
 
     # merge sorted payloads a + b => M
-    i = 0; # walks a
-    j = 0; # walks b
-    k = 0; # walks target M array
+    i = 0 # walks a
+    j = 0 # walks b
+    k = 0 # walks target M array
 
     mergedReturnStates = [] * (len(a.returnState) + len( b.returnStates))
     mergedParents = [] * len(mergedReturnStates)
diff --git a/runtime/Python3/src/antlr4/BufferedTokenStream.py b/runtime/Python3/src/antlr4/BufferedTokenStream.py
index 091ad2a32..919a27335 100644
--- a/runtime/Python3/src/antlr4/BufferedTokenStream.py
+++ b/runtime/Python3/src/antlr4/BufferedTokenStream.py
@@ -131,7 +131,6 @@ class BufferedTokenStream(TokenStream):
     # @see #get(int i)
     #/
     def sync(self, i:int):
-        assert i >= 0
         n = i - len(self.tokens) + 1 # how many more elements we need?
         if n > 0 :
             fetched = self.fetch(n)
diff --git a/runtime/Python3/src/antlr4/PredictionContext.py b/runtime/Python3/src/antlr4/PredictionContext.py
index 8ecc23401..a6e643ea4 100644
--- a/runtime/Python3/src/antlr4/PredictionContext.py
+++ b/runtime/Python3/src/antlr4/PredictionContext.py
@@ -139,7 +139,6 @@ class SingletonPredictionContext(PredictionContext):
             return SingletonPredictionContext(parent, returnState)
 
     def __init__(self, parent:PredictionContext, returnState:int):
-        assert returnState!=ATNState.INVALID_STATE_NUMBER
         hashCode = calculateHashCode(parent, returnState)
         super().__init__(hashCode)
         self.parentCtx = parent
@@ -149,11 +148,9 @@ class SingletonPredictionContext(PredictionContext):
         return 1
 
     def getParent(self, index:int):
-        assert index == 0
         return self.parentCtx
 
     def getReturnState(self, index:int):
-        assert index == 0
         return self.returnState
 
     def __eq__(self, other):
@@ -163,10 +160,8 @@ class SingletonPredictionContext(PredictionContext):
             return False
         elif not isinstance(other, SingletonPredictionContext):
             return False
-        elif hash(self) != hash(other):
-            return False # can't be same if hash is different
         else:
-            return self.returnState == other.returnState and self.parentCtx==other.parentCtx
+            return self.returnState == other.returnState and self.parentCtx == other.parentCtx
 
     def __hash__(self):
         return self.cachedHashCode
@@ -209,8 +204,6 @@ class ArrayPredictionContext(PredictionContext):
 
     def __init__(self, parents:list, returnStates:list):
         super().__init__(calculateListsHashCode(parents, returnStates))
-        assert parents is not None and len(parents)>0
-        assert returnStates is not None and len(returnStates)>0
         self.parents = parents
         self.returnStates = returnStates
 
@@ -279,7 +272,6 @@ def PredictionContextFromRuleContext(atn:ATN, outerContext:RuleContext=None):
 
 
 def merge(a:PredictionContext, b:PredictionContext, rootIsWildcard:bool, mergeCache:dict):
-    assert a is not None and b is not None # must be empty context, never null
 
     # share same graph if both same
     if a==b:
diff --git a/runtime/Python3/src/antlr4/atn/LexerATNSimulator.py b/runtime/Python3/src/antlr4/atn/LexerATNSimulator.py
index 150743b66..68b7c7cda 100644
--- a/runtime/Python3/src/antlr4/atn/LexerATNSimulator.py
+++ b/runtime/Python3/src/antlr4/atn/LexerATNSimulator.py
@@ -539,9 +539,6 @@ class LexerATNSimulator(ATNSimulator):
     # configuration containing an ATN rule stop state. Later, when
     # traversing the DFA, we will know which rule to accept.
     def addDFAState(self, configs:ATNConfigSet) -> DFAState:
-        # the lexer evaluates predicates on-the-fly; by this point configs
-        # should not contain any configurations with unevaluated predicates.
-        assert not configs.hasSemanticContext
 
         proposed = DFAState(configs=configs)
         firstConfigWithRuleStopState = None
diff --git a/runtime/Python3/test/ctest.py b/runtime/Python3/test/ctest.py
index ab5793ddc..19301a0e2 100644
--- a/runtime/Python3/test/ctest.py
+++ b/runtime/Python3/test/ctest.py
@@ -4,6 +4,7 @@ import antlr4
 from parser.cparser import CParser
 from parser.clexer import CLexer
 from datetime import datetime
+import cProfile
 
 class ErrorListener(antlr4.error.ErrorListener.ErrorListener):
 
@@ -34,10 +35,10 @@ def main():
     sub()
     after = datetime.now()
     print(str(after-before))
-    before = after
-    sub()
-    after = datetime.now()
-    print(str(after-before))
+    # before = after
+    # sub()
+    # after = datetime.now()
+    # print(str(after-before))
 
 if __name__ == '__main__':
-    main()
\ No newline at end of file
+    cProfile.run("main()", sort='tottime')
\ No newline at end of file