In HydPy, you are usually very free in defining parameter values. In HydPy-H-Land, for example, you can set the interception capacity (CMax) of each hydrological response unit individually. Sometimes this flexibility is great, but other times its too much. Therefore, many parameter classes support keyword-based options, which allow setting parameter values more simply. In HydPy-H-Land, you can use the "field" keyword to specify the interception capacities of all hydrological response units of type FIELD at ones.

In the mentioned example, this keyword option also shows up in the string representation of the relevant parameter objects. Hence, an automatically saved parameter control file looks as simple as a manually written one. However, this is not the case for many other parameter classes, for example, K of HydPy-H-Land or KapGrenz of HydPy-L-Land.

We should find a general way to incorporate such keyword options in the string representations of more or less individually defined parameter classes. But we need to give some thought to some potentially problematic cases. For example, when one first sets a parameter value via a keyword option but changes it later via a mathematical operation.