code: def save(self, dst, buffer_size=16384):
          
          from shutil import copyfileobj
  
          close_dst = False
          if isinstance(dst, string_types):
              dst = open(dst, "wb")
              close_dst = True
          try:
              copyfileobj(self.stream, dst, buffer_size)
          finally:
              if close_dst:
                  dst.close()
docs: Save the file to a destination path or file object.  If the
          destination is a file object you have to close it yourself after the
          call.  The buffer size is the number of bytes held in memory during
          the copy process.  It defaults to 16KB.
  
          For secure file saving also have a look at :func:`secure_filename`.
  
          :param dst: a filename or open file object the uploaded file
                      is saved to.
          :param buffer_size: the size of the buffer.  This works the same as
                              the `length` parameter of
                              :func:`shutil.copyfileobj`.