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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 getEngineChangelist(self):
 		""" 		Returns the compatible Perforce changelist identifier for the latest installed version of UE4 		"""

		
		# Newer versions of the engine use the key "CompatibleChangelist", older ones use "Changelist"
		version = self._getEngineVersionDetails()
		if 'CompatibleChangelist' in version:
			return int(version['CompatibleChangelist'])
		else:
			return int(version['Changelist'])