class RuboCop::ConfigLoaderResolver

def merge(base_hash, derived_hash, **opts)

arguments, will also be merged. And so on.
with the addition that any value that is a hash, and occurs in both
Return a recursive merge of two hashes. That is, a normal hash merge,
been replaced by parameters returned by the given block.
Returns a new hash where the parameters of the given config hash have 
def merge(base_hash, derived_hash, **opts)
  result = base_hash.merge(derived_hash)
  keys_appearing_in_both = base_hash.keys & derived_hash.keys
  keys_appearing_in_both.each do |key|
    if base_hash[key].is_a?(Hash)
      result[key] = merge(base_hash[key], derived_hash[key], **opts)
    elsif should_union?(base_hash, key, opts[:inherit_mode])
      result[key] = base_hash[key] | derived_hash[key]
    elsif opts[:debug]
      warn_on_duplicate_setting(base_hash, derived_hash, key, opts)
    end
  end
  result
end