diff --git a/seqeval/metrics/sequence_labeling.py b/seqeval/metrics/sequence_labeling.py
index 0be1203..ac56f18 100644
--- a/seqeval/metrics/sequence_labeling.py
+++ b/seqeval/metrics/sequence_labeling.py
@@ -286,19 +286,19 @@ def performance_measure(y_true, y_pred):
         >>> performance_measure(y_true, y_pred)
         {'TP': 3, 'FP': 3, 'FN': 1, 'TN': 4}
     """
-    performace_dict = dict()
+    performance_dict = dict()
     if any(isinstance(s, list) for s in y_true):
         y_true = [item for sublist in y_true for item in sublist]
         y_pred = [item for sublist in y_pred for item in sublist]
-    performace_dict['TP'] = sum(y_t == y_p for y_t, y_p in zip(y_true, y_pred)
-                                if ((y_t != 'O') or (y_p != 'O')))
-    performace_dict['FP'] = sum(((y_t != y_p) and (y_p != 'O')) for y_t, y_p in zip(y_true, y_pred))
-    performace_dict['FN'] = sum(((y_t != 'O') and (y_p == 'O'))
-                                for y_t, y_p in zip(y_true, y_pred))
-    performace_dict['TN'] = sum((y_t == y_p == 'O')
-                                for y_t, y_p in zip(y_true, y_pred))
-
-    return performace_dict
+    performance_dict['TP'] = sum(y_t == y_p for y_t, y_p in zip(y_true, y_pred)
+                                 if ((y_t != 'O') or (y_p != 'O')))
+    performance_dict['FP'] = sum(((y_t != y_p) and (y_p != 'O')) for y_t, y_p in zip(y_true, y_pred))
+    performance_dict['FN'] = sum(((y_t != 'O') and (y_p == 'O'))
+                                 for y_t, y_p in zip(y_true, y_pred))
+    performance_dict['TN'] = sum((y_t == y_p == 'O')
+                                 for y_t, y_p in zip(y_true, y_pred))
+
+    return performance_dict
 
 
 def classification_report(y_true, y_pred, digits=2, suffix=False):