ComfyUI custom node with float input not showing

I'm trying to define a simple custom node but whatever I try I can't seem to get the inputs to show in ComfyUI. I've tried various approaches but it seems anytime I define a custom node with input float it doesn't seem to appear. What am I doing wrong?

import numpy as np
import cv2

class AReferenceSize:
    def __init__(self):
        self.reference_size = None

    @classmethod
    def INPUT_TYPES(cls):
        return {
            "required": {
                "current_size": ("FLOAT", {"default": 0.0}),
                "update": ("BOOLEAN", {"default": False})
            }
        }
    
    RETURN_TYPES = ("FLOAT",)
    FUNCTION = "get_and_update"
    CATEGORY = "example" 

    def get_and_update(self, current_size, update):
        print(f"get_and_update called with current_size: {current_size}, update: {update}")
        if self.reference_size is None or update:
            self.reference_size = current_size
        return (self.reference_size,)

# Register the nodes
NODE_CLASS_MAPPINGS = {
    "AReferenceSize": AReferenceSize  
}

NODE_DISPLAY_NAME_MAPPINGS = {
    "AReferenceSize": "AReference Size"
}