diff --git a/python/tests/test_beagle.py b/python/tests/test_beagle.py
index a9556d02a6..9612e4b651 100644
--- a/python/tests/test_beagle.py
+++ b/python/tests/test_beagle.py
@@ -110,8 +110,9 @@ def get_mismatch_prob(pos, miscall_rate=0.0001):
     :return: Mismatch probabilities.
     :rtype: numpy.ndarray
     """
+    assert isinstance(miscall_rate, float)
     assert 0 <= miscall_rate <= 0.5
-    mu = np.repeat(miscall_rate, len(pos))
+    mu = np.zeros(len(pos), dtype=np.float64) + miscall_rate
     return mu