diff --git a/binarycpython/utils/distribution_functions.py b/binarycpython/utils/distribution_functions.py
index d6a99452af87c021707bd06012bae4695ca087f9..f5d6db84f0dae9943f62fbed43d3681cd788cafe 100644
--- a/binarycpython/utils/distribution_functions.py
+++ b/binarycpython/utils/distribution_functions.py
@@ -1894,7 +1894,7 @@ def Moe_di_Stefano_2017_pdf(options, verbosity=0):
         multiplicity = options["multiplicity"]
 
     # Immediately return 0 if the multiplicity modulator is 0
-    if options["multiplicity_modulator"][multiplicity - 1] == 0:
+    if options["multiplicity_modulator"][int(multiplicity) - 1] == 0:
         verbose_print(
             "\tMoe_di_Stefano_2017_pdf: returning 0 because of the multiplicity modulator being 0",
             verbosity,
@@ -1908,7 +1908,7 @@ def Moe_di_Stefano_2017_pdf(options, verbosity=0):
 
     multiplicity_probability = Moe_di_Stefano_2017_multiplicity_fractions(
         options, verbosity
-    )[multiplicity - 1]
+    )[int(multiplicity) - 1]
     prob_dict["multiplicity"] = multiplicity_probability
     verbose_print(
         "\tMoe_di_Stefano_2017_pdf: Appended multiplicity (mass1 = {}) probability ({}) to the prob dict ({})".format(