Angle of Incidence Calling Problem

[buleskywave]

In my preprocessor function, part of it is used like this:
s1 = Sentinel1Image(input_S1_files)
s0_hh = s1.remove_thermal_noise('HH', algorithm='ESA')
s0_hv = s1.remove_texture_noise('HV')
ia = s1['incidence_angle']

But the code reports an error:
Traceback (most recent call last).
File "mod.py", line 189, in
s1d_product = do_s1denoising(s1, prep_directory)
File "mod.py", line 168, in do_s1denoising
ia = s1['incidenceangle']
TypeError: 'Sentinel1Image' object is not subscriptable

How do I call the incidence angle please?