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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 user_exists(self, 	 user, 	 note=None, 	 loglevel=logging.DEBUG):
 		"""Returns true if the specified username exists. 		@param user: username to check for 		@param note: See send() 		@type user: string 		@rtype: boolean 		"""

		shutit = self.shutit
		shutit.handle_note(note)
		exists = False
		if user == '':
			return exists
		#                v the space is intentional, to avoid polluting bash history.
		# The quotes before XIST are deliberate, to prevent the command from matching the expect.
		ret = self.send(ShutItSendSpec(self,
		                               send=' command id %s && echo E""XIST || echo N""XIST' % user,
		                               expect=['NXIST', 'EXIST'],
		                               echo=False,
		                               loglevel=loglevel,
		                               ignore_background=True))
		if ret:
			exists = True
		# sync with the prompt
		self.expect(self.default_expect)
		shutit.handle_note_after(note=note)
		return exists