assign_default_value

# File activemodel/lib/active_model/attribute_set/builder.rb, line 165
      def assign_default_value(name)
        type = additional_types.fetch(name, types[name])
        value_present = true
        value = values.fetch(name) { value_present = false }

        if value_present
          delegate_hash[name] = Attribute.from_database(name, value, type)
        elsif types.key?(name)
          attr = default_attributes[name]
          if attr
            delegate_hash[name] = attr.dup
          else
            delegate_hash[name] = Attribute.uninitialized(name, type)
          end
        end
      end