docs: function (newValue) {
              if (isElement(newValue)) {
                  this.options.drop.accept = newValue;
  
                  return this;
              }
  
              // test if it is a valid CSS selector
              if (trySelector(newValue)) {
                  this.options.drop.accept = newValue;
  
                  return this;
              }
  
              if (newValue === null) {
                  delete this.options.drop.accept;
  
                  return this;
              }
  
              return this.options.drop.accept;
          }