Definitely possible, although this can also be done with the output from bode_plot and the Numpy argmin function, I suspect.

If you (or someone) want to contribute code to do this, we can put it either in the main package or in the MATLAB compatibility module.

Here is roughly how I solved it for me, I don't have time for providing a pull request, but maybe someone writing the pull request can get inspired.

import scipy
import numpy as np
def bandwidth(sys,dbgain=-3):
  result=scipy.optimize.root(lambda s:control.matlab.freqresp(sys,s)[0][0]-control.matlab.dcgain(sys)*10**(dbgain/20),1)
  if result.success:
    return np.abs(result.x)[0]
  else:
    raise Exception(result.message)

Looks like merged #889 closes this?

I have not used control in years, but I am happy it got solved