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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def download(ui, repo, clname, **opts):
 	"""download a change from the code review server 	Download prints a description of the given change list 	followed by its diff, downloaded from the code review server. 	"""

	if codereview_disabled:
		raise hg_util.Abort(codereview_disabled)

	cl, vers, patch, err = DownloadCL(ui, repo, clname)
	if err != "":
		return err
	ui.write(cl.EditorText() + "\n")
	ui.write(patch + "\n")
	return