import originpro as op
wks = op.new_sheet()
fn=op.path('e') + r'Samples\Curve Fitting\Gaussian.dat'
wks.from_file(fn, False)
model2 = op.NLFit('Gauss')
model2.set_data(wks, 0, 1)
model2.set_lbound('y0','>','6')
model2.set_ubound('A','<','800')
model2.fit()