user: Extract the special guests that Taylor Swift had on her 1989 Tour in 2015. Separate them with a comma.

assistant: Ed Sheeran, Dan Reynolds, Martha Hunt, Gigi Hadid, Little Big Town, Echosmith, Cara Delevingne, Mariska Hargitay, Rachel Platten, Mariska Hargitay, Gigi Hadid, Kendall Jenner, Serena Williams, Martha Hunt, Karlie Kloss, Cara Delevingne, The Weeknd, Heidi Klum, United States women's national soccer team, Lily Aldridge, Lena Dunham, Gigi Hadid, Hailee Steinfeld, Nick Jonas, Gigi Hadid, Martha Hunt, Lily Aldridge, Candice Swanepoel, Behati Prinsloo, Karlie Kloss, Uzo Aduba, Lorde, Jason Derulo, Andy Grammer, Serayah, Sam Hunt, Andreja Pejić, Lily Donaldson, Walk the Moon, MKTO, Nico & Vinz, Fetty Wap, Ciara and Russell Wilson, Fifth Harmony, Little Mix, Joan Baez, Julia Roberts, Ryan Tedder of OneRepublic, Kobe Bryant, Uzo Aduba, Chris Rock, Matt LeBlanc, Sean O'Pry, Mary J. Blige, Natalie Maines of the Dixie Chicks, Ellen DeGeneres, Alanis Morissette, Beck, St. Vincent, John Legend, Selena Gomez, Lisa Kudrow, Justin Timberlake, OMI, Avril Lavigne, Wiz Khalifa, The Band Perry, Sydney Sierota of Echosmith, Dierks Bentley, Kelsea Ballerini, Steven Tyler of Aerosmith, Alison Krauss, Leona Lewis, Mick Jagger of The Rolling Stones, Nelly, Haim, Keith Urban, Charli XCX, Ellie Goulding, Miranda Lambert, Tove Lo, Dwyane Wade, Pitbull, Ricky Martin, Alessia Cara, Idina Menzel

user: which band sold the most albums of all time?

assistant: The Beatles.

Perhaps unsurprisingly, British rock band The Beatles are top of the list for best-selling artists worldwide, with 183 million units certified sales.

The Beatles were an English rock band, formed in Liverpool in 1960, that comprised John Lennon, Paul McCartney, George Harrison and Ringo Starr. They are regarded as the most influential band of all time and were integral to the development of 1960s counterculture and popular music's recognition as an art form.

user: How do I cast on a knitting project?

assistant: Casting on is how to make the first row of stitches. Each method of casting on can look and feel slightly different (such as various levels of stretchiness and flexibility) so most knitters have their preferred cast on method. Many use the long-tail cast on method which can work for many projects.  First, measure the length of yarn that is about 4 times as long as the width of your project. For example, if the width of your project is 10 inches, measure out a 40 inch piece of yarn. Next, time a slip knot. Then, place the slip knot on your dominant hand’s needle with the yarn tail closest to you (the tail is the length you measured out). Hold both strands of yarn with your non-dominant hand. Spread the two strands of yarn out with your thumb and forefinger, then bring the knitting needle in your right hand to the front of the tail of yarn draped over your thumb. Bring the needle back, up and through the loop toward your thumb loop, then push the needle back and under the forefinger loop, allowing the needle to catch the forefinger loop and allowing the thumb loop to fall off under the needle. That’s your first cast on stitch. Repeat the steps for the total number of stitches you need.