ENH: permits unary pos for period objects

Author: deniederhut

pandas/core/generic.py

@@ -25,6 +25,7 @@
     is_list_like,
     is_dict_like,
     is_re_compilable,
+    is_period_arraylike,
     pandas_dtype)
 from pandas.core.dtypes.cast import maybe_promote, maybe_upcast_putmask
 from pandas.core.dtypes.inference import is_hashable
@@ -1038,7 +1039,7 @@ def __neg__(self):
 
     def __pos__(self):
         values = com._values_from_object(self)
-        if is_bool_dtype(values):
+        if (is_bool_dtype(values) or is_period_arraylike(values)):
             arr = values
         elif (is_numeric_dtype(values) or is_timedelta64_dtype(values)):
             arr = operator.pos(values)