Export fixtures from customs of standard fields

I checked some hidden standard fields from Maintenance Visit doctype and I need export that to my app, how can I do that using fixtures?
Now I’m just exporting the custom fields from there:

fixtures = fixtures = [                                                                                                                                                  
        "Custom Script", "Property Setter",                                                                                                                              
                {"dt":"Custom Field",  "filters": [["dt", "in", ("Maintenance Visit", "Maintenance Visit Purpose", "Quotation", "Customer")]]}

Is the Property Setter, but it’s not working sometimes.
I’ll debug it.