UniProt Uploadlists identifier type labelSource:
UniProt Uploadlists identifier type label
Character: an ID type label, as shown in the table at
Character: either "from" or "to": direction of the mapping.
Character: the UniProt Uploadlists specific ID type label, or the input unchanged if it could not be translated (still might be a valid identifier name). This is the label that one can use in UniProt Uploadlists (ID Mapping) queries.
ensembl_id_type("entrez") #>  "entrez" #  "GeneID"