diff --git a/.vs/ProjectSettings.json b/.vs/ProjectSettings.json
new file mode 100644
index 0000000..f8b4888
--- /dev/null
+++ b/.vs/ProjectSettings.json
@@ -0,0 +1,3 @@
+{
+  "CurrentProjectSetting": null
+}
\ No newline at end of file
diff --git a/.vs/VSWorkspaceState.json b/.vs/VSWorkspaceState.json
new file mode 100644
index 0000000..6b61141
--- /dev/null
+++ b/.vs/VSWorkspaceState.json
@@ -0,0 +1,6 @@
+{
+  "ExpandedNodes": [
+    ""
+  ],
+  "PreviewInSolutionExplorer": false
+}
\ No newline at end of file
diff --git a/.vs/mol_property/v17/.suo b/.vs/mol_property/v17/.suo
new file mode 100644
index 0000000..36391f5
Binary files /dev/null and b/.vs/mol_property/v17/.suo differ
diff --git a/.vs/slnx.sqlite b/.vs/slnx.sqlite
new file mode 100644
index 0000000..758f307
Binary files /dev/null and b/.vs/slnx.sqlite differ
diff --git a/mol_property/pka/predictor.py b/mol_property/pka/predictor.py
index 86e87ad..c0f52c6 100644
--- a/mol_property/pka/predictor.py
+++ b/mol_property/pka/predictor.py
@@ -1,7 +1,7 @@
 # -*- coding: utf-8
 
 import os
-from sklearn.externals import joblib
+import joblib
 from .data_utils import DataUtils
 
 class PkaPredictor(object):