Optional. Metadata filters that will be applied to the memories to be purged. Filters are defined using disjunctive normal form (OR of ANDs). For example: filter_groups: [{filters: [{key: "author", value: {string_value: "agent 123"}, op: EQUAL}]}, {filters: [{key: "label", value: {string_value: "travel"}, op: EQUAL}, {key: "author", value: {string_value: "agent 321"}, op: EQUAL}]}] would be equivalent to the logical expression: (metadata.author = "agent 123" OR (metadata.label = "travel" AND metadata.author = "agent 321")).