remove old set_mutable_field() functions (duplicate of immutable argument)
remove old set_mutable_field() functions (duplicate of immutable argument)

vishesh/pycket,cderici/pycket,cderici/pycket,vishesh/pycket,pycket/pycket,magnusmorton/pycket,krono/pycket,magnusmorton/pycket,cderici/pycket,samth/pycket,magnusmorton/pycket,pycket/pycket,vishesh/pycket,krono/pycket,samth/pycket,krono/pycket,pycket/pycket,samth/pycket