What are elements of irony in Jimmy Valentine?

In "A Retrieved Reformation" by O. Henry (sometimes known as "Jimmy Valentine"), irony is present in several ways. One example is when Jimmy, a skilled safecracker, decides to go straight after falling in love. This is ironic because his criminal expertise ultimately helps him in his redemption. Another instance of irony is when Jimmy, who was previously known for breaking into safes, ends up saving a child trapped in one, showcasing his transformation.