fallback to pathlib2 for older python

python/pyarrow/parquet.py

@@ -362,7 +362,7 @@ class ParquetDatasetPiece(object):
 
     Parameters
     ----------
-    path : str
+    path : str or pathlib.Path
         Path to file in the file system where this piece is located
     partition_keys : list of tuples
       [(column name, ordinal index)]

python/pyarrow/tests/conftest.py

@@ -16,7 +16,11 @@
 # under the License.
 
 import pytest
-import pathlib
+
+try:
+    import pathlib
+except ImportError:
+    import pathlib2 as pathlib  # py2 compat
 
 
 groups = [