Poor error when passing faulty indices in matrix data

[PascalLesage]

Passing indices with faulty keys results in a ValueError: setting an array element with a sequence..

_, _ = presamples.create_presamples_package(matrix_data=[(samples, bad_indices, 'technosphere')])

Yields:

---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-82-5166baacb765> in <module>()
      1 _, _ = presamples.create_presamples_package( presamples.create_presamples_package(matrix_data=[(samples, bad_indices, 'technosphere')])

C:\mypy\anaconda\envs\bw\lib\site-packages\presamples\packaging.py in create_presamples_package(matrix_data, parameter_data, name, id_, overwrite, dirpath, seed)
    295                 "{} and {}".format(samples.shape[1], num_iterations))
    296 
--> 297         indices, metadata = format_matrix_data(indices, kind, *other)
    298 
    299         if samples.shape[0] != indices.shape[0]:

C:\mypy\anaconda\envs\bw\lib\site-packages\presamples\packaging.py in format_matrix_data(indices, kind, dtype, row_formatter, metadata)
    203     if dtype is None and row_formatter is None and metadata is None:
    204         try:
--> 205             return FORMATTERS[kind](indices)
    206         except KeyError:
    207             raise KeyError("Can't find formatter for {}".format(kind))

C:\mypy\anaconda\envs\bw\lib\site-packages\presamples\packaging.py in format_technosphere_presamples(indices)
    101             TYPE_DICTIONARY.get(row[2], row[2])
    102         )
--> 103     return format_matrix_data(indices, 'technosphere', dtype, func, metadata)
    104 
    105 

C:\mypy\anaconda\envs\bw\lib\site-packages\presamples\packaging.py in format_matrix_data(indices, kind, dtype, row_formatter, metadata)
    213         array = np.zeros(len(indices), dtype=dtype)
    214         for index, row in enumerate(indices):
--> 215             array[index] = row_formatter(row)
    216 
    217         return array, metadata

ValueError: setting an array element with a sequence.

Include an exception in the validator with a better error message.