为什么fscore的值大于1？

fScore = gScore + hScore

def a_star_search(graph, start, goal):
    open_set = {start}
    came_from = {}
    g_score = {node: float('inf') for node in graph}
    g_score[start] = 0
    f_score = {node: float('inf') for node in graph}
    f_score[start] = heuristic_cost_estimate(start, goal)

    while open_set:
        current = min(open_set, key=lambda node: f_score[node])
        
        if current == goal:
            return reconstruct_path(came_from, current)
        
        open_set.remove(current)
        for neighbor in graph[current]:
            tentative_g_score = g_score[current] + distance(current, neighbor)
            
            if tentative_g_score < g_score[neighbor]:
                came_from[neighbor] = current
                g_score[neighbor] = tentative_g_score
                f_score[neighbor] = g_score[neighbor] + heuristic_cost_estimate(neighbor, goal)
                if neighbor not in open_set:
                    open_set.add(neighbor)
    
    return None

def heuristic_cost_estimate(start, goal):
    # 这里应该实现一个合理的启发式函数，例如欧几里得距离或曼哈顿距离
    pass

def distance(node1, node2):
    # 这里应该实现计算两个节点之间实际距离的函数
    pass

def reconstruct_path(came_from, current):
    # 这里应该实现重构路径的函数
    pass