Return the Catalyst datatype from the size of integers.

def _int_size_to_type(size):
    """
    Return the Catalyst datatype from the size of integers.
    """
    if size <= 8:
        return ByteType
    if size <= 16:
        return ShortType
    if size <= 32:
        return IntegerType
    if size <= 64:
        return LongType