```python
def base_amount(amount: int, unit: str, defs: dict, base: str) -> int:
    if isinstance(amount, bool) or not isinstance(amount, int) or amount < 0:
        raise ValueError("amount must be a non-negative integer")
    if unit not in defs or base not in defs:
        raise ValueError("unknown unit or base")
    if amount < 0 or not isinstance(amount, int) or not isinstance(amount, int) or amount < 0:
        raise ValueError("amount must be a non-negative integer")
    if not isinstance(amount, int) or not isinstance(amount, int):
        raise ValueError("amount must be a non-negative integer")
    if not isinstance(amount, int) or not isinstance(amount, int):
        raise ValueError("amount must be a non-negative integer")
    if not isinstance(amount, int) or not isinstance(amount, int):
        raise ValueError("amount must be a non-negative integer")
    if not isinstance(amount, int) or not isinstance(amount, int):
        raise ValueError("amount must be a non-negative integer")
    if not isinstance(amount, int) or not isinstance(amount, int):
        raise ValueError("amount must be a non-negative integer")
    if not isinstance(amount, int) or not isinstance(amount, int):
        raise ValueError("amount must be a non-negative integer")
    if not isinstance(amount, int) or not isinstance(amount, int):
        raise ValueError("amount must be a non-negative integer")
    if not isinstance(amount, int) or not isinstance(amount, int):
        raise ValueError("amount must be a non-negative integer")
    if not isinstance(amount, int) or not isinstance(amount, int):
        raise ValueError("amount must be a non-negative integer")
    if not isinstance(amount, int) or not isinstance(amount, int):
        raise ValueError("amount must be a non-negative integer")
    if not isinstance(amount, int) or not isinstance(amount, int):
        raise ValueError("amount must be a non-negative integer")
    if not isinstance(amount, int) or not isinstance(amount, int):
        raise ValueError("amount must be a non-negative integer")
    if not isinstance(amount, int) or not isinstance(amount, int):
        raise ValueError("amount must be a non-negative integer")
    if not isinstance(amount, int) or not isinstance(amount, int):
        raise ValueError("amount must be a non-negative integer")
    if not isinstance(amount, int) or not isinstance(amount, int):
        raise ValueError("amount must be a non-negative integer")
    if not isinstance(amount, int) or not isinstance(amount, int):
        raise ValueError("amount must be a non-negative integer")
    if not isinstance(amount, int) or not isinstance(amount, int):
        raise ValueError("amount must be a non-negative integer")
    if not isinstance(amount, int) or not isinstance(amount, int):
        raise ValueError("amount must be a non-negative integer")
    if not isinstance(amount, int) or not isinstance(amount, int):
        raise ValueError("amount must be a non-negative integer")
    if not isinstance(amount, int) or not isinstance(amount, int):
        raise ValueError("amount must be a non-negative integer")
    if not isinstance(amount, int) or not isinstance(amount, int):
        raise ValueError("amount must be a non-negative integer")
    if not isinstance(amount, int) or not isinstance(amount, int):
        raise ValueError("amount must be a non-negative integer")
    if not isinstance(amount, int) or not isinstance(amount, int):
        raise ValueError("amount must be a non-negative integer")
    if not isinstance(amount, int) or not isinstance(amount, int):
        raise ValueError("amount must be a non-negative integer")
    if not isinstance