Hi Dita,
Below is an example of usage in Python:
from mintpy.utils import readfile, utils as ut
data, atr = readfile.read('velocity.h5', datasteName='velocity')
txn = ut.transect_lalo(data, atr, start_lalo=[32.0, 110.0], end_lalo=[32.2, 111.0])
Cheers,
Yunjun