FeatureCollection validation

[YuriyRomanyshynUA]

Hi)

class FeatureCollection(GeoJSON):
   # ...
   def errors(self):
       return self.check_list_errors(lambda x: x.errors(), self.features)
   # ...
   # possible solution
   def errors(self):
      def check(item):
         if isinstance(item, geojson.Feature):
            return item.errors()
         else:
            raise GeoJSONError ...

      return self.check_list_errors(check, self.features)

I think it would be better if first check object type and if it is instance of GeoJSON only then call 'errors' method, if it is not, raise exception with appropriate message, because if you put in collection something different from GeoJSON object you will get a confusing error. For example if you append native dict in collection you will get bewildering:

"AttributeError: 'dict' object has no attribute 'errors'"