diff --git a/lib/waipy/cwa/cross_wavelet.py b/lib/waipy/cwa/cross_wavelet.py
index f95e638..b602ddb 100644
--- a/lib/waipy/cwa/cross_wavelet.py
+++ b/lib/waipy/cwa/cross_wavelet.py
@@ -16,8 +16,9 @@
 import pylab
 from pylab import *
 import matplotlib.pyplot as plt
-import cmath
+import math #for compatibility
 import pandas as pd
+import math
 
 
 def cross_wavelet(wave1, wave2):