Validate memory size for Lambda Function
    :param memory_value: The memory size specified in the Function
    :return: The provided memory size if it is valid

def validate_memory_size(memory_value):
    """ Validate memory size for Lambda Function
    :param memory_value: The memory size specified in the Function
    :return: The provided memory size if it is valid
    """
    memory_value = int(positive_integer(memory_value))
    if memory_value not in MEMORY_VALUES:
        raise ValueError("Lambda Function memory size must be one of:\n %s" %
                         ", ".join(str(mb) for mb in MEMORY_VALUES))
    return memory_value