code: def write_from_file(library, session, filename, count):
      
      return_count = ViUInt32()
      ret = library.viWriteFromFile(session, filename, count, return_count)
      return return_count, ret
docs: Take data from a file and write it out synchronously.
  
      Corresponds to viWriteFromFile function of the VISA library.
  
      :param library: the visa library wrapped by ctypes.
      :param session: Unique logical identifier to a session.
      :param filename: Name of file from which data will be read.
      :param count: Number of bytes to be written.
      :return: Number of bytes actually transferred, return value of the library call.
      :rtype: int, :class:`pyvisa.constants.StatusCode`