class Hash

def deep_transform_keys(&block)

Experimental RBS support (using type sampling data from the type_fusion project). 

def deep_transform_keys: () -> untyped

This signature was generated using 1 sample from 1 application.

# => {"PERSON"=>{"NAME"=>"Rob", "AGE"=>"28"}}
hash.deep_transform_keys{ |key| key.to_s.upcase }

hash = { person: { name: 'Rob', age: '28' } }

nested hashes and arrays.
This includes the keys from the root hash and from all
Returns a new hash with all keys converted by the block operation. 
def deep_transform_keys(&block)
  _deep_transform_keys_in_object(self, &block)
end