Among the businesses in Tempe, list the attribute of the business with a medium review count.
Tempe is a city; high review count refers to review_count = 'High'
SELECT DISTINCT T3.attribute_name FROM Business AS T1 INNER JOIN Business_Attributes AS T2 ON T1.business_id = T2.business_id INNER JOIN Attributes AS T3 ON T2.attribute_id = T3.attribute_id WHERE T1.city = 'Tempe' AND T1.review_count = 'Medium'