MET filters
With the integration of NanoAOD format (!47 (merged), when it will be merged), we can re-implement the MET filters for the analysis. These can be easily accessed from the NanoAOD according to the documentation.
We should probably make a new class for that (that can be inspired from the one for triggers, implemented in the shears part in shears!142 (merged)), instead of a function in Utils as was done before.