diff --git a/snakehouse/build.py b/snakehouse/build.py
index a787cd465752808c933a6cc2286ae87392406085..1d7992bdaf5eabe78d01622746935611e9aae910 100644
--- a/snakehouse/build.py
+++ b/snakehouse/build.py
@@ -11,8 +11,8 @@ def build(extensions: tp.List[tp.Union[Multibuild, Extension]], *args, **kwargs)
             returns.append(multi_build)
         elif isinstance(multi_build, Multibuild):
             multi_build.generate()
+            returns.append(multi_build.for_cythonize())
         else:
             raise ValueError('Invalid value in list, expected either an instance of Multibuild '
                              'or an Extension')
-        returns.append(multi_build.for_cythonize())
     return cythonize(returns, *args, **kwargs)