rmChars(chars) {
    if(!chars) return
    let rm = {}
    if(_.isArray(chars)) {
      for(let i = 0; i < chars.length; i++) {
        rm[chars[i].id] = true
      }
    } else {
      rm[chars.id] = true
    }
    this.remove(rm)
  }
Delete the given chars.
@param {Char|Char[]} chars