diff --git a/src/gui_qt/dsc/glass_dialog.py b/src/gui_qt/dsc/glass_dialog.py
new file mode 100644
index 0000000..260ba2c
--- /dev/null
+++ b/src/gui_qt/dsc/glass_dialog.py
@@ -0,0 +1,8 @@
+from ..Qt import QtWidgets
+
+
+class TgCalculator(QtWidgets.QDialog):
+    def __init__(self, parent=None):
+        super().__init__(parent=parent)
+
+
diff --git a/src/nmreval/data/dsc.py b/src/nmreval/data/dsc.py
index a621797..f69dd0f 100644
--- a/src/nmreval/data/dsc.py
+++ b/src/nmreval/data/dsc.py
@@ -23,10 +23,8 @@ class DSC(Points):
         y = np.asarray(y).reshape(np.asarray(x).shape)
 
         x, unique = np.unique(x, return_index=True)
-
-        if 'y_err' in kwargs:
-            _yerr = kwargs['y_err']
-            _yerr = np.asarray(_yerr).reshape(np.asarray(x).shape)
+        if kwargs.get('y_err', None) is not None:
+            _yerr = np.asarray(kwargs['y_err']).reshape(np.asarray(x).shape)
             kwargs['y_err'] = _yerr[unique]
 
         super().__init__(x, y[unique], **kwargs)
diff --git a/src/nmreval/io/hdfreader.py b/src/nmreval/io/hdfreader.py
index b5b85cb..8c681ce 100644
--- a/src/nmreval/io/hdfreader.py
+++ b/src/nmreval/io/hdfreader.py
@@ -388,10 +388,11 @@ class HdfReader(HdfNode):
                 if multi:
                     var_key = None
 
-        try:
-            value = param_dic[var_key.lower()]
-        except KeyError:
-            pass
+        if var_key is not None:
+            try:
+                value = param_dic[var_key.lower()]
+            except KeyError:
+                pass
 
         return value