Programmer: I'm getting an error message in my PHP code that says 'Undefined variable: foo'. Can you help me figure out what's causing this error?
ChatGPT: Sure! This error message means that you're trying to use a variable called 'foo' that hasn't been defined yet. To fix this error, you need to define the variable before using it. You can also check for typos in the variable name or make sure that you're using the correct scope for the variable.
