"""File Parsing."""


def get_product_ids_from_csv(filepath):
    """Get product IDs from CSV."""
    product_ids = set()
    with open(filepath) as f:
        for index, line in enumerate(f):
            if line == '\n':
                continue
            value = _get_value(line, index == 0)
            if value:
                product_ids.add(value)
    return product_ids


def _get_value(line, is_header):
    if not is_header:
        return int(line)
    try:
        return int(line)
    except ValueError:
        pass