def quanta_to_string(lx, ly, lz):
    """Pretty print monomials with quanta lx, ly, lz."""
    string = ""
    string += "X" * lx
    string += "Y" * ly
    string += "Z" * lz
    # if lx:
    #     string += 'x'
    # if lx > 1:
    #     string += '^{}'.format(lx)
    # if ly:
    #     string += 'y'
    # if ly > 1:
    #     string += '^{}'.format(ly)
    # if lz:
    #     string += 'z'
    # if lz > 1:
    #     string += '^{}'.format(lz)
    return string