exposed cast policy as property

dios/dios.py

@@ -37,7 +37,7 @@ from typing import Union, Any
 
 
 class DictOfSeries:
-    f""" A data frame where every column has its own index.
+    """ A data frame where every column has its own index.
 
     DictOfSeries is a collection of pd.Series's which aim to be as close as possible similar to
     pd.DataFrame. The advantage over pd.DataFrame is, that every `column` has its own row-index,
@@ -62,16 +62,17 @@ class DictOfSeries:
         if None, the index-type is inferred each time a series is inserted
         or deleted.
         
-    cast_policy : str {_CAST_POLICIES}
+    cast_policy : str
         Policy to use for down-casting an itype.
     """
 
     def __init__(self, data=None, columns=None, index=None, itype=None, cast_policy='save', fastpath=False):
-        
+
+        self.cast_policy = cast_policy
+
         # we are called internally
         if fastpath:
             self._itype = itype or ObjItype
-            self._policy = cast_policy
             if data is not None:
                 self._data = data
             else:
@@ -94,10 +95,6 @@ class DictOfSeries:
                 if itype is not None:
                     self._itype = get_itype(itype)
 
-            if cast_policy not in _CAST_POLICIES:
-                raise ValueError(f"downcast_policy must be one of {_CAST_POLICIES}")
-            self._policy = cast_policy
-
             cols = pd.Index([] if columns is None else columns)
             if not cols.is_unique:
                 raise ValueError("columns must be unique")
@@ -252,6 +249,16 @@ class DictOfSeries:
             raise ValueError(method)
         return res if res.is_unique else res.unique()
 
+    @property
+    def cast_policy(self):
+        return self._policy
+
+    @cast_policy.setter
+    def cast_policy(self, policy):
+        if policy not in _CAST_POLICIES:
+            raise ValueError(f"policy must be one of {_CAST_POLICIES}")
+        self._policy = policy
+
     @property
     def itype(self):
         if self._itype == 'INFER':