se adiciona field.Function

FossilOrigin-Name: 45a288bc30ad9b25fed59cd01c89bd2f7632926083384a7853c3b753a4d7f95b

facho/model/__init__.py

@@ -28,7 +28,18 @@ class ModelBase(object, metaclass=ModelMeta):
     def __getitem__(self, key):
         return self._xml_attributes[key]
 
+    def __before_xml__(self):
+        pass
+
+    def _hook_before_xml(self):
+        self.__before_xml__()
+        for field in self._fields.values():
+            if hasattr(field, '__before_xml__'):
+                field.__before_xml__()
+
     def to_xml(self):
+        self._hook_before_xml()
+
         tag = self.__name__
         ns = ''
         if self._namespace_prefix is not None:

facho/model/fields/__init__.py

@@ -1,5 +1,6 @@
 from .attribute import Attribute
 from .many2one import Many2One
 from .model import Model
+from .function import Function
 
 __all__ = [Attribute, Many2One, Model]

facho/model/fields/field.py

@@ -19,3 +19,9 @@ class Field:
         if name not in namespaces:
             raise KeyError("namespace %s not found" % (name))
         inst._namespace_prefix = name
+
+    def _call(self, inst, method, *args):
+        call = getattr(inst, method or '', None)
+
+        if callable(call):
+            return call(*args)