Set the unobservable sequence data before this base

    :param tlen: target homopolymer length
    :param qlen: query homopolymer length
    :param nt: nucleotide
    :param p: p is the probability of attributing this base to the unobserved error
    :type tlen: int
    :type qlen: int
    :type nt: char
    :type p: float

def set_unobserved_before(self,tlen,qlen,nt,p):
    """Set the unobservable sequence data before this base

    :param tlen: target homopolymer length
    :param qlen: query homopolymer length
    :param nt: nucleotide
    :param p: p is the probability of attributing this base to the unobserved error
    :type tlen: int
    :type qlen: int
    :type nt: char
    :type p: float

    """
    self._unobservable.set_before(tlen,qlen,nt,p)