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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 process(self):
 """ Do the bare minimum processing to make a mesh useful. Does this by: 1) removing NaN and Inf values 2) merging duplicate vertices If self._validate: 3) Remove triangles which have one edge of their rectangular 2D oriented bounding box shorter than tol.merge 4) remove duplicated triangles Returns self: trimesh.Trimesh Current mesh """

        # if there are no vertices or faces exit early
        if self.is_empty:
            return self

        # avoid clearing the cache during operations
        with self._cache:
            self.remove_infinite_values()
            self.merge_vertices()
            # if we're cleaning remove duplicate
            # and degenerate faces
            if self._validate:
                self.remove_duplicate_faces()
                self.remove_degenerate_faces()
        # since none of our process operations moved vertices or faces,
        # we can keep face and vertex normals in the cache without recomputing
        # if faces or vertices have been removed, normals are validated before
        # being returned so there is no danger of inconsistent dimensions
        self._cache.clear(exclude=['face_normals',
                                   'vertex_normals'])
        self.metadata['processed'] = True
        return self