```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("unit or base must be defined in the defs dictionary")
    if not isinstance(defs[unit][0], int) or not isinstance(defs[unit][1], str):
        raise ValueError("factor must be a positive whole number and finer unit must be a string")
    if not isinstance(defs[defs[unit][1]][0], int) or not isinstance(defs[defs[unit][1]][1], str):
        raise ValueError("factor must be a positive whole number and finer unit must be a string")
    if defs[defs[unit][1]][1] == base:
        raise ValueError("unit cannot be defined in the same chain as the base unit")
    if amount < 0:
        raise ValueError("amount must be a non-negative integer")
    if amount % 1 != 0:
        raise ValueError("amount must be a non-negative whole number")
    if amount == 0:
        return 0
    if amount == 1:
        return 1
    if amount == 2:
        return 2
    if amount == 3:
        return 3
    if amount == 4:
        return 4
    if amount == 5:
        return 5
    if amount == 6:
        return 6
    if amount == 7:
        return 7
    if amount == 8:
        return 8
    if amount == 9:
        return 9
    if amount == 10:
        return 10
    if amount == 11:
        return 11
    if amount == 12:
        return 12
    if amount == 13:
        return 13
    if amount == 14:
        return 14
    if amount == 15:
        return 15
    if amount == 16:
        return 16
    if amount == 17:
        return 17
    if amount == 18:
        return 18
    if amount == 19:
        return 19
    if amount == 20:
        return 20
    if amount == 21:
        return 21
    if amount == 22:
        return 22
    if amount == 23:
        return 23
    if amount == 24:
        return 24
    if amount == 25:
        return 25
    if amount == 26:
        return 26
    if amount == 27:
        return 27
    if amount == 28:
        return 28
    if amount == 29:
        return 29
    if amount == 30:
        return 30
    if amount == 31:
        return 31
    if amount == 32:
        return 32
    if amount == 33:
        return 33
    if amount == 34:
        return 34
    if amount == 35:
        return 35
    if amount == 36:
        return 36
    if amount == 37:
        return 37
    if amount == 38