@staticmethod
def _get_gc_content(sequence, length):
    """Get GC content and proportions.

        Parameters
        ----------
        sequence : str
            The complete sequence of the contig.
        length : int
            The length of the sequence contig.

        Returns
        -------
        x : dict
            Dictionary with the at/gc/n counts and proportions

        """
    at = sum(map(sequence.count, ['A', 'T']))
    gc = sum(map(sequence.count, ['G', 'C']))
    n = length - (at + gc)
    at_prop = at / length
    gc_prop = gc / length
    n_prop = n / length
    return {'at': at, 'gc': gc, 'n': n, 'at_prop': at_prop, 'gc_prop':
        gc_prop, 'n_prop': n_prop}
