From e36d295af40451553eca2f7ce529b462511ba3e5 Mon Sep 17 00:00:00 2001
From: Jon Mease <jon.mease@gmail.com>
Date: Tue, 3 Sep 2019 11:10:59 -0400
Subject: [PATCH] Make operation_kwargs private to the Histogram class

---
 holoviews/element/chart.py                 | 17 ++---------------
 holoviews/operation/element.py             |  4 ++--
 holoviews/tests/operation/testoperation.py |  6 +++---
 3 files changed, 7 insertions(+), 20 deletions(-)

diff --git a/holoviews/element/chart.py b/holoviews/element/chart.py
index cada4c9a09..bd75381a68 100644
--- a/holoviews/element/chart.py
+++ b/holoviews/element/chart.py
@@ -182,27 +182,14 @@ def __init__(self, data, edges=None, **params):
         elif isinstance(data, tuple) and len(data) == 2 and len(data[0])+1 == len(data[1]):
             data = data[::-1]
 
-        self._operation_kwargs = params.pop('operation_kwargs', None)
+        self._operation_kwargs = params.pop('_operation_kwargs', None)
 
         super(Histogram, self).__init__(data, **params)
 
-    @property
-    def operation_kwargs(self):
-        """
-        If Histogram was generated by the holoviews.operation.histogram
-        operation, this property contains a dictionary of keyword-value
-        arguments that can be used with the histogram operation to regenerate
-        this histogram from the same input dataset.
-
-        If Histogram was created directly using the constructor, property
-        will be None.
-        """
-        return self._operation_kwargs
-
     def clone(self, *args, **kwargs):
         return super(Histogram, self).clone(
             *args,
-            operation_kwargs=copy.deepcopy(self.operation_kwargs),
+            _operation_kwargs=copy.deepcopy(self._operation_kwargs),
             **kwargs
         )
 
diff --git a/holoviews/operation/element.py b/holoviews/operation/element.py
index 0cf6ab07c1..2132cda351 100644
--- a/holoviews/operation/element.py
+++ b/holoviews/operation/element.py
@@ -663,10 +663,10 @@ def _process(self, element, key=None):
         # from the same data set, but we can also generate a histogram using
         # a different dataset that will share the exact same bins.
         exclusions = {'log', 'bin_range', 'num_bins'}
-        params['operation_kwargs'] = {
+        params['_operation_kwargs'] = {
             k: v for k, v in self.p.items() if k not in exclusions
         }
-        params['operation_kwargs']['bins'] = list(edges)
+        params['_operation_kwargs']['bins'] = list(edges)
         return Histogram((edges, hist), kdims=[element.get_dimension(selected_dim)],
                          label=element.label, **params)
 
diff --git a/holoviews/tests/operation/testoperation.py b/holoviews/tests/operation/testoperation.py
index 526b249fa0..399172fa15 100644
--- a/holoviews/tests/operation/testoperation.py
+++ b/holoviews/tests/operation/testoperation.py
@@ -167,7 +167,7 @@ def test_histogram_operation_kwargs(self):
 
         # Check operation kwargs for histogram generated with operation
         self.assertEqual(
-            op_hist.operation_kwargs,
+            op_hist._operation_kwargs,
             {'dimension': 'y',
              'normed': False,
              'dynamic': False,
@@ -176,7 +176,7 @@ def test_histogram_operation_kwargs(self):
 
         # Test that operation_kwargs is preserved through clone
         self.assertEqual(
-            op_hist.clone().operation_kwargs,
+            op_hist.clone()._operation_kwargs,
             {'dimension': 'y',
              'normed': False,
              'dynamic': False,
@@ -185,7 +185,7 @@ def test_histogram_operation_kwargs(self):
 
         # Check that operation kwargs is None for histogram generated directly
         # from the Histogram constructor
-        self.assertIsNone(hist.operation_kwargs)
+        self.assertIsNone(hist._operation_kwargs)
 
     @da_skip
     def test_dataset_histogram_dask(self):