Fix exception for indexing with multiple `...`s
@@ -248,7 +248,7 @@ cpdef tuple complete_slice_list(list slice_list, Py_ssize_t ndim):
n_ellipses += 1
ellipsis = i
if n_ellipses > 1:
- raise ValueError('Only one Ellipsis is allowed in index')
+ raise IndexError("an index can only have a single ellipsis ('...')")
n = ndim - <Py_ssize_t>len(slice_list) + n_newaxes
if n_ellipses > 0:
