Field: rename is_oid to oid.

lima/fields.py

@@ -17,15 +17,15 @@ class Field(abc.FieldABC):
 
         val: An optional constant value for the field.
 
-        is_oid: If ``True``, marks this field as a field whose value can be
-            used to identify an object. A schema must not end up with more than
-            one identifier field.
+        oid: If ``True``, marks this field as a field whose value can be used
+            to identify an object. A schema must not end up with more than one
+            identifier field.
 
     .. versionadded:: 0.3
         The ``val`` parameter.
 
     .. versionadded:: 0.4
-        The ``is_oid`` parameter.
+        The ``oid`` parameter.
 
     :attr:`attr`, :attr:`get` and :attr:`val` are mutually exclusive.
 
@@ -43,7 +43,7 @@ class Field(abc.FieldABC):
     instance.
 
     '''
-    def __init__(self, *, attr=None, get=None, val=None, is_oid=False):
+    def __init__(self, *, attr=None, get=None, val=None, oid=False):
         if sum(v is not None for v in (attr, get, val)) > 1:
             raise ValueError('attr, get and val are mutually exclusive.')
 
@@ -59,7 +59,7 @@ def __init__(self, *, attr=None, get=None, val=None, is_oid=False):
         elif val is not None:
             self.val = val
 
-        self.is_oid = is_oid
+        self.oid = oid
 
 
 class Boolean(Field):