Imagine you are tasked with developing a large language model that generates Python code snippets. To ensure the generated code is high-quality, you decide to implement a penalty function during the decoding process. Describe how you would design this penalty function to be flexible enough to enforce the following three distinct requirements: 1) adherence to a specific style guide (e.g., line length, variable naming conventions), 2) avoidance of specific deprecated library functions, and 3) inclusion of explanatory comments for any code block longer than 10 lines. For each requirement, explain what the penalty function would look for in the generated text.