wave:dashboard

1{ 'datasetSystemName1': 
2    {'field1': ['!value1']}, 
3  'datasetSystemName2': 
4    {'field1': ['!value1', '!value2'],
5     'field2': ['!value3']} }

The dataset System Name is in the left panel of the edit page for the dataset. (If your org has namespaces, include the namespace prefix and two underscores before the dataset system name.) The field is a dimension in the dataset. To find the name, click the Explore icon to open the widget, select Show SAQL from the Options menu, and look for dimension names in the “group by” statements. The value is a field in the Salesforce object. To find the name, go to Setup, locate the object you want, and select Fields. Use the Field Name (also known as the API name). For custom fields, use the name with "__c" at the end.

Note: Only dimensions that have a list widget on the dashboard can be included in the filter attribute JSON.