code: def RdatabasesBM(host=rbiomart_host):
      
      biomaRt = importr("biomaRt")
      print(biomaRt.listMarts(host=host))
docs: Lists BioMart databases through a RPY2 connection.
  
      :param host: address of the host server, default='www.ensembl.org'
  
      :returns: nothing