CLN: move routines for filling missing data from core/common.py to core/missing.py

Author: stahlous

pandas/core/categorical.py

@@ -10,6 +10,7 @@
 from pandas.core.algorithms import factorize
 from pandas.core.base import PandasObject, PandasDelegate
 import pandas.core.common as com
+from pandas.core.missing import interpolate_2d
 from pandas.util.decorators import cache_readonly, deprecate_kwarg
 
 from pandas.core.common import (ABCSeries, ABCIndexClass, ABCPeriodIndex, ABCCategoricalIndex,
@@ -1312,7 +1313,7 @@ def fillna(self, value=None, method=None, limit=None):
         if method is not None:
 
             values = self.to_dense().reshape(-1, len(self))
-            values = com.interpolate_2d(
+            values = interpolate_2d(
                 values, method, 0, None, value).astype(self.categories.dtype)[0]
             values = _get_codes_for_values(values, self.categories)