Wrong except option for nested entities

Good day. I have a problem with except option. If I use it on entity Patient like this

Patient::Entity.represent(patient, except: [testssets: [:patient]]).as_json

all works great, but I have an infinite recursion if use it on opposite entity Testsset

Testsset::Entity.represent(testsset, except: [patient: [:testssets]]).as_json

I think that there's a problem with Exposure::Base#serializeable_value. All works fine in first case because it is one-to-many relation and handled by this code

partial_output.map(&:serializable_hash)

In second case it is handled by this code (with options argument)

partial_output.serializable_hash(options)

And lately options generated for a nested entity are rewritten in Options#merge method like this

options = {except: [:testssets]}
new_options = {except: [{patient: [:testssets]}]}
options.merge(new_options)

So, now we have except fields for a nested entity such as for the parent.
It seems that this code is broken and options hash should be passed in both cases. And except fields shouldn't be merged.

Read lib/grape_entity/exposure/base.rb at Exposure::Base#serializeable_value and lib/grape_entity/options.rb at Options#merge, then reproduce both Patient::Entity and Testsset::Entity examples from the issue. Done means nested except options no longer cause infinite recursion and the requested nested fields remain excluded.