<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def WriteTaskStart(self):
 """Writes task start information. Raises: IOError: if the storage type is not supported or when the storage writer is closed. OSError: if the storage type is not supported or when the storage writer is closed. """

    self._RaiseIfNotWritable()

    if self._storage_type != definitions.STORAGE_TYPE_TASK:
      raise IOError('Unsupported storage type.')

    task_start = self._task.CreateTaskStart()
    self._storage_file.WriteTaskStart(task_start)