def read_bam_file(bam_path):
    """Read from a QC-pass bam file.

    Parameters
    ----------
    bam_path : str
        Name of a 10x bam file
    Returns
    -------
    bam_file : pysam.AlignmentFile
        Iterator over possorted_genome_bam.bam file
    """
    import pysam
    return pysam.AlignmentFile(bam_path, mode='rb')
