changes some little things in database init like typeerror to valueerror and so on

navipy/database/__init__.py

@@ -376,7 +376,7 @@ database
             if rowid is np.nan:
                 raise ValueError('rowid must not be nan')
         if (posorient is None) and (rowid is None):
-                Exception('posorient and rowid can not be both None')
+                raise Exception('posorient and rowid can not be both None')
         if posorient is not None:
                 rowid = self.get_posid(posorient)
         # Read images
@@ -466,6 +466,8 @@ database
         return toreturn
 
     def denormalise_image(self, image, cmaxminrange):
+        if not isinstance(image,np.ndarray):
+            raise TypeError('image must be np.array')
         if len(image.shape) != 3:
             raise Exception('image should be 3D array')
         if image.shape[2] != len(self.channels):
@@ -473,7 +475,7 @@ database
                              number of channels {}'.format(
                 len(self.channels)))
         if not isinstance(cmaxminrange, pd.Series):
-            raise Exception('cmaxminrange should be a pandas Series')
+            raise TypeError('cmaxminrange should be a pandas Series')
         if cmaxminrange.empty:
             raise Exception('cmaxminrange must not be empty')
         for chan_n in self.channels: