code: def sequence_type(seq):
      '''Validates a coral.sequence data type.
  
      :param sequence_in: input DNA sequence.
      :type sequence_in: any
      :returns: The material - 'dna', 'rna', or 'peptide'.
      :rtype: str
      :raises: ValueError
  
      '''
      if isinstance(seq, coral.DNA):
          material = 'dna'
      elif isinstance(seq, coral.RNA):
          material = 'rna'
      elif isinstance(seq, coral.Peptide):
          material = 'peptide'
      else:
          raise ValueError('Input was not a recognized coral.sequence object.')
      return materiaf sequence_type(seq):
      '''Validates a coral.sequence data type.
  
      :param sequence_in: input DNA sequence.
      :type sequence_in: any
      :returns: The material - 'dna', 'rna', or 'peptide'.
      :rtype: str
      :raises: ValueError
  
      '''
      if isinstance(seq, coral.DNA):
          material = 'dna'
      elif isinstance(seq, coral.RNA):
          material = 'rna'
      elif isinstance(seq, coral.Peptide):
          material = 'peptide'
      else:
          raise ValueError('Input was not a recognized coral.sequence object.')
      return material
docs: Validates a coral.sequence data type.
  
      :param sequence_in: input DNA sequence.
      :type sequence_in: any
      :returns: The material - 'dna', 'rna', or 'peptide'.
      :rtype: str
      :raises: ValueError