Evaluate the collective function of references cited together in a given text segment.
Classify their combined role into one of the following categories: 'method', 'background', or 'result'.

Text:Almost all of the commonly used neural simulation packages now have a Python interface (Eppler et al., 2008; Goodman and Brette, 2009; Hines et al., 2009; Cornelis et al., 2012).
Category: