优先使用 字符串插值 来代替 字符串串联。
# bad
email_with_name = user.name + ' <' + user.email + '>'
# good
email_with_name = #{user.name} <#{user.email}>
# good
email_with_name = format('%s <%s>', user.name, user.email)
Consider padding string interpolation code with space. It more clearly sets th
