from typing import Dict
from typing import Any


def generate_bulkiness_section(cat_properties: Dict[str, Any]) -> str:
    """Generate the CAT bulkiness input section."""
    def replace_None(x):
        return "NULL" if x is None else x
    if "bulkiness" not in cat_properties:
        return "bulkiness: False"
    bulkiness = cat_properties['bulkiness']
    string = "bulkiness:\n"
    for key in {"h_lim", "d"}:
        string += f"{' ':>10}{key}: {replace_None(bulkiness[key])}\n"
    return string