I unchecked the Lower Bound configuration in the signal property, saved the setting as an xml file, imported it and got the error.
Traceback (most recent call last):
File "c:\users\владислав\nfb_studio\nfb_studio\experiment_view.py", line 510, in actionImport
ex = Experiment.import_xml(data)
File "c:\users\владислав\nfb_studio\nfb_studio\experiment.py", line 198, in import_xml
n.setLowerBound(float(signal_data.get("fBandpassLowHz", n.default_lower_bound)))
TypeError: float() argument must be a string or a number, not 'NoneType'
I unchecked the Lower Bound configuration in the signal property, saved the setting as an xml file, imported it and got the error.