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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def from_geojson(cls, filename):
 """Load vector from geojson."""

        with open(filename) as fd:
            geometry = json.load(fd)

        if 'type' not in geometry:
            raise TypeError("%s is not a valid geojson." % (filename,))

        return cls(to_shape(geometry), WGS84_CRS)