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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 getContactUIDForUser(self):
 """Get the UID of the user associated with the authenticated user """

        membership_tool = api.get_tool("portal_membership")
        member = membership_tool.getAuthenticatedMember()
        username = member.getUserName()
        r = self.portal_catalog(
            portal_type="Contact",
            getUsername=username
        )
        if len(r) == 1:
            return r[0].UID