Returns the possible values for a specific filter. Not all filters listed
by comex_filters() have a values endpoint.
Arguments
- filter
Filter name. Available filters by type:
general: "country", "economicBlock", "state", "urf", "ncm", "section"
city: "country", "economicBlock", "state", "city", "heading", "chapter", "section"
historical: "country", "state"
- type
Data type: "general", "city", or "historical"
- language
Language: "pt", "en", or "es". Default: "en"
- verbose
Logical. If TRUE, display progress messages. Default: FALSE