My impression is that the convention is a ! suffix means both that 1) There's another, similar, method without the suffix. 2) The ! version has some side effe

My impression is that the convention is a ! suffix means both that 1) There's another, similar, method without the suffix. 2) The ! version has some side effect (usually mutating something or throwing an exception) that the non-! doesn't, which doesn't mean that the non-! has no side effects (`ApplicationRecord#save` and `#save!` both have side effects, but only `#save!` throws on failure). — Is there any idiomatic Ruby library where ! methods don't follow this convention?