Returns the number of neighbors of site n.
        In graph terms, simply returns degree
        of node corresponding to site n.
        :param n: index of site
        :return (int):

def get_coordination_of_site(self, n):
        """
        Returns the number of neighbors of site n.
        In graph terms, simply returns degree
        of node corresponding to site n.
        :param n: index of site
        :return (int):
        """
        number_of_self_loops = sum([1 for n, v in self.graph.edges(n) if n == v])
        return self.graph.degree(n) - number_of_self_loops