index may be unique + added notw on keyError

Author: tp

pandas/core/indexes/base.py

@@ -3430,8 +3430,8 @@ def _get_string_slice(self, key, use_lhs=True, use_rhs=True):
 
     def slice_indexer(self, start=None, end=None, step=None, kind=None):
         """
-        For an ordered index, compute the slice indexer for input labels and
-        step
+        For an ordered or unique index, compute the slice indexer for input
+        labels and step.
 
         Parameters
         ----------
@@ -3446,6 +3446,11 @@ def slice_indexer(self, start=None, end=None, step=None, kind=None):
         -------
         indexer : slice
 
+        Raises
+        ------
+        KeyError : If key does not exist, or key is not unique and index is
+            not ordered.
+
         Notes
         -----
         This function assumes that the data is sorted, so use at your own peril