def count_commas(s: str) -> int:
    """
    count commas:
      - english comma [,](\u002c)
      - Chinese full-width comma [，](\uff0c)
      - Chinese seperator / Japanese comma [、](\u3001)
    """
    count = 0
    for c in s:
        if c in "\u002c\uff0c\u3001":
            count += 1
    return count