code: def download_go_basic_obo(obo="go-basic.obo", prt=sys.stdout, loading_bar=True):
      
      if not os.path.isfile(obo):
          http = "http://purl.obolibrary.org/obo/go"
          if "slim" in obo:
              http = "http://www.geneontology.org/ontology/subsets"
              # http = 'http://current.geneontology.org/ontology/subsets'
          obo_remote = "{HTTP}/{OBO}".format(HTTP=http, OBO=os.path.basename(obo))
          dnld_file(obo_remote, obo, prt, loading_bar)
      else:
          if prt is not None:
              prt.write("  EXISTS: {FILE}\n".format(FILE=obo))
      return obo
docs: Download Ontologies, if necessary.