code: def check_key_value_struct(data)
        if data.kind_of?(Hash)
          return check_key_value_hash(data)
        end
        if data.kind_of?(Array) && !data.empty?
          data.each do |item|
            return false if !check_key_value_hash(item)
          end
          return true
        end
        return false
      end
docs: Checks if all elements of the array or hash passed are hashes and have
   ':key' and ':value' keys only.