Document return type for FiniteDifferenceUniform.__call__

1 files changed, 2 insertions, 0 deletions

diff --git a/diff.py b/diff.py
index 2430a0e..bd9a135 100644
--- a/diff.py
+++ b/diff.py
@@ -86,6 +86,8 @@ class FiniteDifferenceUniform(object):
         :param array_like arr: Array to differentiate.
         :param int axis: Axis along which to differentiate.
         :param float dx: Spacing between array elements.
+        :return: derivative of arr
+        :rtype: Numpy array, same shape and type as arr.
         """
         coeff   = self._coeffs
         div     = self._div