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: Sony NWZE464GRN Walkman MP3 player
Product description: The Sony E-Series Walkman MP3 Player delivers up to 50 hours of music -with video and photo playback plus FM radio just to sweeten the deal. With delicious colors, Windows drag and drop functionality and digitally restorative Sony Clear Audio Technologies, the E-Series is bling to the ears and eyes.
Product feature: Digital music, video & photo player with FM radio, 2-Inch QVGA (320x240) highbrightness, color LCD, Rechargeable battery with up to 50 hours audio playback, Easy content transfer with Media Go for Windows or drag/drop compatible with Windows XP, Windows Vista, Windows 7
Product brand: Sony
Target attributes: Battery Life
Answer: attribute: battery life
value: up to 50 hours audio
source: product feature
attribute: battery life
value: up to 50 hours of music
source: product description