code: def assign_reads_to_database(query_fasta_fp, database_fasta_fp, output_fp,
                               params=None):
      
      if params is None:
          params = {}
      if '-out' not in params:
          params['-out'] = 'blast9'
      blat = Blat(params=params)
  
      result = blat([query_fasta_fp, database_fasta_fp, output_fp])
      return result['output']
docs: Assign a set of query sequences to a reference database
  
      query_fasta_fp : absolute file path to query sequences
      database_fasta_fp : absolute file path to the reference database
      output_fp : absolute file path of the output file to write
      params : dict of BLAT specific parameters.
  
      This method returns an open file object. The output format
      defaults to blast9 and should be parsable by the PyCogent BLAST parsers.