fix linting error

Author: charlesdong1991

Diff for: pandas/tests/test_strings.py

@@ -9,10 +9,11 @@
 from numpy.random import randint
 import pytest
 
+import pandas.compat as compat
+
 from pandas import DataFrame, Index, MultiIndex, Series, concat, isna, notna
 import pandas.core.strings as strings
 import pandas.util.testing as tm
-import pandas.compat as compat
 from pandas.util.testing import assert_index_equal, assert_series_equal