Validate (circular) links in Ribasim python on write

[evetion]

Now Julia gives an error, but ideally we know that beforehand.

As mentioned by @DanielTollenaar.

[visr]

Yeah since #2112 Python validates this on add. It doesn't seem optimal to validate on input and output side because the add API is regularly bypassed.

[DanielTollenaar]

For the time being we've implemented this in Ribasim-NL models:

    def validate_link_source_destination(self):
        """Check if links exist with reversed source-destination
        """
        df = self.link.df

        # on tuples we can easily check duplicates irrespective of order
        duplicated_links = pd.Series(
            list(zip(np.minimum(df["from_node_id"], df["to_node_id"]),
                           np.maximum(df["from_node_id"], df["to_node_id"]))), index=df.index).duplicated(keep=False)

        # if links are duplicated in reversed source-destination we raise an Exception
        if duplicated_links.any():
            raise ValueError(f"Links found with reversed source-destination: {list(df[duplicated_links].reset_index()[["link_id", "from_node_id", "to_node_id"]].to_dict(orient="index").values())}")

I run this before writing models which gives me a clear Exception before writing to disk. Would be great if this was the default when model.use_validation = True: