Warning with fsig frequency set to 0

When applying fsigs with:

kat.signals.apply(kat.M_ETM_HR.phi, 1, 180) # amplitude = 1, phase = 180 degree

You see the error:

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Error from Finesse:
*** Error:  Line `fsig sig_M_ETM_HR_phi M_ETM_HR phase 0
180.0 1.0 ': Signal frequency must be positive and greater
than 0Hz
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Need a check before running file whether fsigs are used and if so should be greater than 0