Instruction: Parse the product information to locate the target attribute, and then provide the extracted value of the target attribute and its source in the output, specifying None if the attribute is not present.

Input:
Product title: WIIPU sexy cocktail party evening club wear open back midi Dress (J188) (yellow)
Product description: sexy cocktail party evening club wear open back midi Dress
Product feature: Imported, please confirm the size before you order, materil:Polyester,Microfiber, Shipping Information: View shipping rates and policies, ASIN: B06XYSSND1, Date first listed on Amazon: March 31, 2017, Average Customer Review: 2.3 out of 5 stars 6 customer reviews
Product price: $3.99 - $18.99
Product brand: WIIPU
Target attributes: Length
Answer: attribute: length
value: midi
source: product description
attribute: length
value: midi
source: product title