code: function coerce(name, value) {
    var def = 1
    var result
    var level
  
    /* istanbul ignore if - Handled by unified in v6.0.0 */
    if (typeof value === 'boolean') {
      result = [value]
    } else if (value == null) {
      result = [def]
    } else if (
      typeof value === 'object' &&
      (typeof value[0] === 'number' ||
        typeof value[0] === 'boolean' ||
        typeof value[0] === 'string')
    ) {
      result = value.concat()
    } else {
      result = [1, value]
    }
  
    level = result[0]
  
    if (typeof level === 'boolean') {
      level = level ? 1 : 0
    } else if (typeof level === 'string') {
      if (level === 'off') {
        level = 0
      } else if (level === 'on' || level === 'warn') {
        level = 1
      } else if (level === 'error') {
        level = 2
      } else {
        level = 1
        result = [level, result]
      }
    }
  
    if (level < 0 || level > 2) {
      throw new Error(
        'Invalid severity `' +
          level +
          '` for `' +
          name +
          '`, ' +
          'expected 0, 1, or 2'
      )
    }
  
    result[0] = level
  
    return result
  }
docs: Coerce a value to a severity--options tuple.