Allow inferred_type = 'empty'

Author: h-vetinari

pandas/core/strings.py

@@ -1822,8 +1822,9 @@ def _validate(data):
                                      'not MultiIndex')
 
         # see src/inference.pyx which can contain string values
-        allowed_types = ['string', 'unicode', 'mixed', 'mixed-integer']
-        if isinstance(data, ABCSeries): 
+        allowed_types = ['string', 'unicode', 'empty',
+                         'mixed', 'mixed-integer']
+        if isinstance(data, ABCSeries):
             allowed_types = allowed_types + ['bytes']
 
         values = data if isinstance(data, Index) else data.values