is_number?

# File activemodel/lib/active_model/validations/numericality.rb, line 94
      def is_number?(raw_value, precision, scale)
        if options[:only_numeric] && !raw_value.is_a?(Numeric)
          return false
        end

        !parse_as_number(raw_value, precision, scale).nil?
      rescue ArgumentError, TypeError
        false
      end