few bug solving

baseprocessor.py

@@ -370,7 +370,7 @@ class HDF5Container(BaseProcessor):
             for base_unit_str in unit:
                 expo = unit[base_unit_str]
                 base_unit = self._get_units(base_unit_str)
-                new_unit = new_unit * base_unit ** expo
+                new_unit = new_unit * base_unit**expo
             return new_unit
         if (data is not None) and isinstance(data, dict) and list(unit)[0] in data:
             for key in unit:
@@ -435,7 +435,7 @@ class HDF5Container(BaseProcessor):
                         self._save_data(name_full + "/" + key, data[key], "", unit)
         else:
             try:
-                if len(data) == 0:
+                if data is None or len(data) == 0:
                     return
             except TypeError:
                 data = np.array([data])