snake not eating

[cleopython]

so my ball python who is about 4 years old hasn't eaten in about 4 weeks. she is not an aggressive snake and stopped striking her prey a while ago, so I usually just leave the rat in her terrarium and she'll sometimes eat it (but she skips meals a lot) Some of those times when she skipped meals was when she was about to shed but she isn't about to shed right now so I don't know why she isn't eating.