Attr-cache the base model class exposed by db.Model property.

peewee.py

@@ -464,6 +464,8 @@ class DatabaseProxy(Proxy):
  """
  Proxy implementation specifically for proxying `Database` objects.
  """
+ __slots__ = ('obj', '_callbacks', '_Model')
+
  def connection_context(self):
  return ConnectionContext(self)
  def atomic(self, *args, **kwargs):
@@ -476,8 +478,10 @@ def savepoint(self):
  return _savepoint(self)
  @property
  def Model(self):
- class Meta: database = self
- return type('BaseModel', (Model,), {'Meta': Meta})
+ if not hasattr(self, '_Model'):
+ class Meta: database = self
+ self._Model = type('BaseModel', (Model,), {'Meta': Meta})
+ return self._Model
 
 
 class ModelDescriptor(object): pass
@@ -3455,8 +3459,10 @@ def get_noop_select(self, ctx):
 
  @property
  def Model(self):
- class Meta: database = self
- return type('BaseModel', (Model,), {'Meta': Meta})
+ if not hasattr(self, '_Model'):
+ class Meta: database = self
+ self._Model = type('BaseModel', (Model,), {'Meta': Meta})
+ return self._Model
 
 
 def __pragma__(name):