Classify the following sentence into either an imperative, declarative, interrogative, or exclamatory sentence.
Please turn off the lights.
The sentence "Please turn off the lights" is an imperative sentence.
Complete the following task based on the instruction and optional input provided.### Instruction:
Classify the following sentence into either an imperative, declarative, interrogative, or exclamatory sentence.

### Input:
Please turn off the lights.

### Output:
The sentence "Please turn off the lights" is an imperative sentence.