pyat fails to load .mat from matlab with element VariableMultipole

[oscarxblanco]

Dear all,
I get the following error when loading a .mat file saved in matlab.

>>> ring = at.load_mat('ring.mat')
Traceback (most recent call last):
  File "/home/oblanco/Documents/public/progs/pyenv/pyenvat/lib/python3.11/site-packages/at/lattice/elements.py", line 296, in __setattr__
    value = self._conversions.get(key, _nop)(value)
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
TypeError: only length-1 arrays can be converted to Python scalars

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/oblanco/Documents/public/progs/pyenv/pyenvat/lib/python3.11/site-packages/at/load/matfile.py", line 202, in load_mat
    return Lattice(
           ^^^^^^^^
  File "/home/oblanco/Documents/public/progs/pyenv/pyenvat/lib/python3.11/site-packages/at/lattice/lattice_object.py", line 191, in __init__
    super(Lattice, self).__init__(elems)
  File "/home/oblanco/Documents/public/progs/pyenv/pyenvat/lib/python3.11/site-packages/at/lattice/lattice_object.py", line 1478, in params_filter
    for elem in elem_filter(params, *args):
  File "/home/oblanco/Documents/public/progs/pyenv/pyenvat/lib/python3.11/site-packages/at/load/matfile.py", line 140, in ringparam_filter
    for elem in elem_iterator(params, *args):
  File "/home/oblanco/Documents/public/progs/pyenv/pyenvat/lib/python3.11/site-packages/at/load/matfile.py", line 105, in _matfile_generator
    yield Element.from_dict(kwargs, index=index, check=check, quiet=quiet)
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/oblanco/Documents/public/progs/pyenv/pyenvat/lib/python3.11/site-packages/at/load/utils.py", line 365, in element_from_dict
    element = cls(*(arg for arg in elem_args if arg is not None), **elem_dict)
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/oblanco/Documents/public/progs/pyenv/pyenvat/lib/python3.11/site-packages/at/lattice/variable_elements.py", line 84, in __init__
    AmplitudeB = self._set_params(AmplitudeB, mode, 'B', **kwargs)
                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/oblanco/Documents/public/progs/pyenv/pyenvat/lib/python3.11/site-packages/at/lattice/variable_elements.py", line 122, in _set_params
    self._set_sine(ab, **kwargs)
  File "/home/oblanco/Documents/public/progs/pyenv/pyenvat/lib/python3.11/site-packages/at/lattice/variable_elements.py", line 132, in _set_sine
    setattr(self, 'Frequency' + ab, frequency)
  File "/home/oblanco/Documents/public/progs/pyenv/pyenvat/lib/python3.11/site-packages/at/lattice/elements.py", line 299, in __setattr__
    self.FamName, key, exc),)
    ^^^^^^^^^^^^
AttributeError: 'VariableMultipole' object has no attribute 'FamName'

While checking the file content with scipy.io.loadmat I see it is saved, but, pyat doesn't see it.

>>> r['THERING1'][3][0][0][0]['FamName']
array(['KIDDK'], dtype='<U5')