How to create custom Expectations for pandas

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Hi, I have successfully created a custom expectation around PandasDataset. While execution, it gets correctly picked up. However, in the HTML result, the details are incomplete. How can I achieve a proper output in HTML format as well? So far, only the custom expectation name and arguments of that method are populated in HTML. I also want some meaningful information to be shown in that report, as to why the expectation failed, what was observed and what is the actual value. Any help is appreciated.


Could you add some examples of how to implement custom multi-column expectations? I’m just not sure what to return instead of x: ...).