code: def determine_seq_type(seq, aa_alphabet):
      
      
      if all([x in 'ACGTacgt' for x in seq]):
          return 'ntseq'
      elif all([x in aa_alphabet for x in seq]):
          return 'aaseq'
      elif all([x in aa_alphabet + '[]{}0123456789,']):
          return 'regex'
docs: Determine the type of a sequence.
      
      Parameters
      ----------
  
      seq : str
          Sequence to be typed.
      aa_alphabet : str
          String of all characters recoginized as 'amino acids'. (i.e. the keys
          of codons_dict: aa_alphabet = ''.join(codons_dict.keys())  )
  
      Returns
      -------
      seq_type : str
          The type of sequence (ntseq, aaseq, regex, None) seq is.
      
      Example
      --------
      >>> determine_seq_type('TGTGCCAGCAGTTCCGAAGGGGCGGGAGGGCCCTCCCTGAGAGGTCATGAGCAGTTCTTC', aa_alphabet)
      'ntseq'
      >>> determine_seq_type('CSARDX[TV]GNX{0,}', aa_alphabet)
      'regex