code: def is_dll(self):
          
  
          DLL_flag = IMAGE_CHARACTERISTICS['IMAGE_FILE_DLL']
  
          if ( DLL_flag & self.FILE_HEADER.Characteristics) == DLL_flag:
              return True
  
          return False
docs: Check whether the file is a standard DLL.
  
          This will return true only if the image has the IMAGE_FILE_DLL flag set.