Deal with missing long_name in quantity parameters (closes #127)

climix/metadata.py

@@ -90,10 +90,10 @@ PARAMETER_KINDS = {}
 
 @dataclass
 class ParameterQuantity(Parameter):
-    long_name: str
     standard_name: str
     data: Any
     units: str
+    long_name: str = None
 
     @property
     def parameter(self):
@@ -107,12 +107,16 @@ class ParameterQuantity(Parameter):
         if isinstance(data, dict) and len(data) == 1:
             key, value = data.popitem()
             data = parameters[key]
-        return ParameterQuantity(
+        ln = self.long_name
+        if ln is not None:
+            ln = ln.format(**parameters)
+        param = ParameterQuantity(
             ParameterKind.QUANTITY,
-            self.long_name.format(**parameters),
             self.standard_name.format(**parameters),
             data,
-            self.units)
+            self.units,
+            ln)
+        return param
 
 
 PARAMETER_KINDS['quantity'] = ParameterQuantity