code: def mash(self, databasepath):
          
          logging.info('Downloading pre-computed RefSeq MASH sketches')
          # Create the folder in which the database is to be stored
          databasepath = self.create_database_folder(databasepath=databasepath,
                                                     database='mash')
          output_file = os.path.join(databasepath, 'assembly_summary_refseq.txt')
          # Download the assembly summary RefSeq document
          if not os.path.isfile(output_file):
              self.database_download(output_file=output_file,
                                     database_path=databasepath,
                                     target_url='ftp://ftp.ncbi.nih.gov/genomes/ASSEMBLY_REPORTS/'
                                                'assembly_summary_refseq.txt'
                                     )
          # Set the call to create the database
          output_file = os.path.join(databasepath, 'RefSeqSketchesDefaults.msh')
          # Download the database
          if not os.path.isfile(output_file):
              self.database_download(output_file=output_file,
                                     database_path=databasepath,
                                     target_url='https://gembox.cbcb.umd.edu/mash/refseq.genomes.k21s1000.msh',
                                     complete=True)
docs: Download the pre-computed sketch of the RefSeq database, and compress it with gzip
          :param databasepath: path to use to save the database