Please answer a question about the following article about Philadelphia:

The City Planning Commission, tasked with guiding growth and development of the city, has divided the city into 18 planning districts as part of the Philadelphia2035 physical development plan. Much of the city's 1980 zoning code was overhauled from 2007–2012 as part of a joint effort between former mayors John F. Street and Michael Nutter. The zoning changes were intended to rectify incorrect zoning mapping that would streamline future community preferences and development, which the city forecasts an additional 100,000 residents and 40,000 jobs to be added to Philadelphia in 2035.

Which two mayors accomplished the zoning code revamp?
John F. Street and Michael Nutter