A FeatureCollection or Feature loaded through geojson package not parsed

[mattijn]

A GeoJSON object from the geojson package is causing an error. It can be reproduced with the following code snippet:

with open("tests/files_geojson/geometry_collection.geojson") as f:
    data = geojson.load(f)
topo = topojson.extract(data)

~/topojson/topojson/extract.py in extract_featurecollection(self, geom)
    224 
    225         # convert FeatureCollection into a dict of features
--> 226         # TODO: this will trigger an error as there is no self.obj
    227         obj = self.obj
    228         data = {}

AttributeError: 'Extract' object has no attribute 'obj'

This counts both for the type geojson.FeatureCollection as well as geojson.Feature

[mattijn]

This issue is fixed through #5