Describe the bug
A recent, major, update has overhauled bumps. This has broken fitting on our end. I am still investigating the underlying issue. @pkienzle would like to keep backwards compatibility, and said he is planning to run old bumps tests against the latest bumps to see what has changed.

Error when running a SasView fit using sasview main branch and bumps master branch:

sas.qtgui.Perspectives.Fitting.FitThread - ERROR - Fitting failed: Traceback (most recent call last):
File "sasview\src\sas\qtgui\Perspectives\Fitting\FitThread.py", line 79, in compute
result = list(map(map_apply, inputs))
^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "sasview\src\sas\qtgui\Perspectives\Fitting\FitThread.py", line 19, in map_apply
return arguments0
^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "sasview\src\sas\qtgui\Perspectives\Fitting\FitThread.py", line 16, in map_getattr
return getattr(classInstance, classFunc)(*args)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "sasview\src\sas\sascalc\fit\BumpsFitting.py", line 260, in fit
models.append(SasFitness(model=dataset.get_model(), data=dataset.get_data(), constraints=dataset.constraints,
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "sasview\src\sas\sascalc\fit\BumpsFitting.py", line 120, in init
self._define_pars()
File "sasview\src\sas\sascalc\fit\BumpsFitting.py", line 138, in _define_pars
self._pars[k] = parameter.Parameter(value=value, bounds=bounds,
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "bumps\bumps\parameter.py", line 595, in init
bounds = (float(bounds[0]), float(bounds[1]))
^^^^^^^^^^^^^^^^
TypeError: float() argument must be a string or a real number, not 'NoneType'
14:43:48 - root - ERROR - float() argument must be a string or a real number, not 'NoneType'
None
14:43:48 - sas.qtgui.Perspectives.Fitting.FittingWidget - ERROR - Traceback (most recent call last):
File "sasview\src\sas\qtgui\Perspectives\Fitting\FittingWidget.py", line 2115, in fitComplete
self.chi2 = res.fitness
^^^^^^^^^^^
AttributeError: 'str' object has no attribute 'fitness'

Expected behavior
The fit should run without errors.

SasView version (please complete the following information):

• Version: main branch

Additional context
This does not affect the release branch due to the version pin we have there.