code: function validate(inputs, options) {
      let hasError = false
  
      if (inputs.length >= 2) {
          console.error("ERROR: the input file should not be multiple.")
          hasError = true
      }
      if (inputs.length >= 1 && !fs.existsSync(inputs[0])) {
          console.error("ERROR: the input file should exist.")
          hasError = true
      }
      if (options.output != null && Array.isArray(options.output)) {
          console.error("ERROR: --output option should not be multiple.")
          hasError = true
      }
      if (inputs.length >= 1 && options.output != null && path.resolve(inputs[0]) === path.resolve(options.output)) {
          console.error("ERROR: --output option should not be the same as the input file.")
          hasError = true
      }
      if (options.manifest != null && Array.isArray(options.manifest)) {
          console.error("ERROR: --manifest option should not be multiple.")
          hasError = true
      }
  
      return !hasError
  }
docs: Validate options.
  
  @param {string[]} inputs - The target files.
  @param {object} options - The option object.
  @returns {void}
  @private