def transcript_pos_transform(tobj, transcript_pos):
    """
	transform the transcript position to genomic position
	0-based
	if strand is "-", return position of strand.
	"""
    length = 0
    strand = tobj.genomic_iv.strand
    genomic_pos = -1
    for i in tobj.genomic_exons:
        if transcript_pos < length + i.length:
            if strand == '+':
                genomic_pos = transcript_pos - length + i.start
            else:
                genomic_pos = i.start_d - (transcript_pos - length)
            break
        length += i.length
    return genomic_pos
