diff --git a/python/src/com/jetbrains/python/PyNames.java b/python/src/com/jetbrains/python/PyNames.java
index ec858b21ee73..93aedc4c3fe3 100644
--- a/python/src/com/jetbrains/python/PyNames.java
+++ b/python/src/com/jetbrains/python/PyNames.java
@@ -2,8 +2,11 @@ package com.jetbrains.python;
 
 import com.google.common.collect.ImmutableSet;
 import org.jetbrains.annotations.NonNls;
+import org.jetbrains.annotations.NotNull;
 
-import java.util.*;
+import java.util.Collections;
+import java.util.Map;
+import java.util.TreeMap;
 import java.util.regex.Pattern;
 
 /**
@@ -241,7 +244,7 @@ public class PyNames {
    * @param name what to check
    * @return true iff name is not reserved and is a well-formed identifier.
    */
-  public static boolean isIdentifier(@NonNls String name) {
+  public static boolean isIdentifier(@NotNull @NonNls String name) {
     return ! isReserved(name) && IDENTIFIER_PATTERN.matcher(name).matches(); 
   }
 
diff --git a/python/src/com/jetbrains/python/psi/PyUtil.java b/python/src/com/jetbrains/python/psi/PyUtil.java
index 0ba219a55b8d..42cf7ce1e303 100644
--- a/python/src/com/jetbrains/python/psi/PyUtil.java
+++ b/python/src/com/jetbrains/python/psi/PyUtil.java
@@ -664,7 +664,7 @@ public class PyUtil {
     return name.startsWith("__") && !name.endsWith("__");
   }
 
-  public static boolean isPythonIdentifier(String name) {
+  public static boolean isPythonIdentifier(@NotNull String name) {
     return PyNames.isIdentifier(name);
   }