Find the neighbour-vertices in the triangulation for the given vertex
        (from the data structures of the triangulation)

def identify_vertex_neighbours(self, vertex):
        """
        Find the neighbour-vertices in the triangulation for the given vertex
        (from the data structures of the triangulation)
        """
        vertex = self._permutation[vertex]

        lpl = self.lend[vertex-1]
        lp = lpl

        neighbours = []

        while True:
            lp = self.lptr[lp-1]
            neighbours.append(self.lst[lp-1]-1)
            if (lp == lpl):
                break

        return self._deshuffle_simplices(neighbours)