code: def get_fasta_records(fasta, transcripts):
      
      records = {}
      f = pysam.FastaFile(fasta)
      for transcript in transcripts:
          try:
              sequence, length = f.fetch(transcript), f.get_reference_length(transcript)
          except KeyError:
              msg = 'Transcript "{}" does not exist in transcriptome FASTA file'.format(transcript)
              log.error(msg)
              raise ArgumentError(msg)
          records[transcript] = {'sequence': sequence, 'length': length}
      f.close()
      return records
docs: Return list of transcript records from the given fasta file.
      Each record will be of the form {'sequence_id': {'sequence': 'AAA', 'length': 3}}
  
      trascripts should be provided as a list of sequence id's.