Adopt PEP 484 type hints for C++ types exported to Python
diff --git a/example/eigen.ref b/example/eigen.ref
index 755012f..626c604 100644
--- a/example/eigen.ref
+++ b/example/eigen.ref
@@ -53,3 +53,8 @@
incr_diag OK
symmetric_lower OK
symmetric_upper OK
+double_col(arg0: numpy.ndarray[float32[m, 1]]) -> numpy.ndarray[float32[m, 1]]
+double_row(arg0: numpy.ndarray[float32[1, n]]) -> numpy.ndarray[float32[1, n]]
+double_mat_rm(arg0: numpy.ndarray[float32[m, n]]) -> numpy.ndarray[float32[m, n]]
+sparse_passthrough_r(arg0: scipy.sparse.csr_matrix[float32]) -> scipy.sparse.csr_matrix[float32]
+sparse_passthrough_c(arg0: scipy.sparse.csc_matrix[float32]) -> scipy.sparse.csc_matrix[float32]