+def _BuildDiskTemplateCheck(accept_none):
+ """Builds check for disk template.
+
+ @type accept_none: bool
+ @param accept_none: whether to accept None as a correct value
+ @rtype: callable
+
+ """
+ template_check = ht.TElemOf(constants.DISK_TEMPLATES)
+
+ if accept_none:
+ template_check = ht.TOr(template_check, ht.TNone)
+
+ return ht.TAnd(template_check, _CheckFileStorage)