from mapnik import Map, Layer
proj4 = '+proj=lcc +lat_1=49 +lat_0=49 +lon_0=-95 +k_0=1 +x_0=0 +y_0=0 +ellps=GRS80 +datum=NAD83 +units=m +no_defs'
m = Map(256,256,proj4)
lyr = Layer('Name',proj4)