old_contents: """Null object for the assemblers."""
  
  from os.path import join
  import lib.db as db
  from lib.assemblers.base import BaseAssembler
  
  
  class NoneAssembler(BaseAssembler):
      """Null object for the assemblers."""
  
      def __init__(self, args, db_conn):
          """Build the assembler."""
          super().__init__(args, db_conn)
          self.steps = []
          self.blast_only = True  # Used to short-circuit the assembler
  
      def write_final_output(self, blast_db, query):
          """Output this file if we are not assembling the contigs."""
          prefix = self.final_output_prefix(blast_db, query)
  
          file_name = join(prefix, 'blast_only.fasta')
  
          with open(file_name, 'w') as output_file:
              for row in db.get_sra_blast_hits(self.state['db_conn'], 1):
                  output_file.write('>{}{}\n'.format(
                      row['seq_name'], row['seq_end']))
                  output_file.write('{}\n'.format(row['seq']))
  
new_contents: """Null object for the assemblers."""
  
  from os.path import join
  import lib.db as db
  from lib.assemblers.base import BaseAssembler
  
  
  class NoneAssembler(BaseAssembler):
      """Null object for the assemblers."""
  
      def __init__(self, args, db_conn):
          """Build the assembler."""
          super().__init__(args, db_conn)
          self.steps = []
          self.blast_only = True  # Used to short-circuit the assembler
  
      def write_final_output(self, blast_db, query):
          """Output this file if we are not assembling the contigs."""
          prefix = self.final_output_prefix(blast_db, query)
  
          file_name = '{}.fasta'.format(prefix)
  
          with open(file_name, 'w') as output_file:
              for row in db.get_sra_blast_hits(self.state['db_conn'], 1):
                  output_file.write('>{}{}\n'.format(
                      row['seq_name'], row['seq_end']))
                  output_file.write('{}\n'.format(row['seq']))
  
subject: Change file name for output for no assembler given