Gets the specified example(s) from [SPARQL query service examples page](https://www.wikidata.org/wiki/Wikidata:SPARQL_query_service/queries/examples) using [Wikidata's MediaWiki API](https://www.wikidata.org/w/api.php).
Details
If you are planning on extracting multiple examples, please provide all the names as a single vector for efficiency.
Examples
if (FALSE) { # \dontrun{
sparql_query <- extract_example(c("Cats", "Horses"))
query_wikidata(sparql_query)
# returns a named list with two data frames
# one called "Cats" and one called "Horses"
sparql_query <- extract_example("Largest cities with female mayor")
cat(sparql_query)
query_wikidata(sparql_query)
} # }