<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _validate(self, val: list, log: Optional[Logger] = None) -> Tuple[bool, List[str]]: """ Determine whether val is a valid instance of this array :returns: Success indicator and error list """

        errors = []
        if not isinstance(val, list):
            errors.append(f"{self._variable_name}: {repr(val)} is not an array")
        else:
            for i in range(0, len(val)):
                v = val[i]
                if not conforms(v, self._type, self._context.NAMESPACE):
                    errors.append(f"{self._variable_name} element {i}: {v} is not a {self._type.__name__}")

            if len(val) < self._min:
                errors.append(
                    f"{self._variable_name}: at least {self._min} value{'s' if self._min > 1 else ''} required - "
                    f"element has {len(val) if len(val) else 'none'}")
            if self._max is not None and len(val) > self._max:
                errors.append(
                    f"{self._variable_name}: no more than {self._max} values permitted - element has {len(val)}")

        if log:
            for error in errors:
                log.log(error)
        return not bool(errors), errors