Parameter "filter_method" does not work as intended

[sferics]

The idea of the filter_method parameter for the read_bufr function is to offer the ability to replace the default method all() by any() or some other function. However, the results are not correct yet.

TASK: Find out, where in the code all() needs to be replaced by filter_method - and where not. Maybe some other changes (to bufr_filters.py?) are necessary. Read, understand and implement what is needed.