python甘特图x轴为时间秒数值

python画甘特图时候，取值是秒（x轴）
不知道怎样能将x轴用值（float）来显示，查到的资料也都是日期来的

这两个都是以秒作为x坐标刻度的
https://blog.csdn.net/ainivip/article/details/105945066?ops_request_misc=&request_id=&biz_id=102&utm_term=python%E7%94%98%E7%89%B9%E5%9B%BE&utm_medium=distribute.pc_search_result.none-task-blog-2~all~sobaiduweb~default-3-105945066.pc_ask&spm=1018.2226.3001.4449
https://blog.csdn.net/yaologos/article/details/108616902?ops_request_misc=%257B%2522request%255Fid%2522%253A%2522165932733816781647510270%2522%252C%2522scm%2522%253A%252220140713.130102334..%2522%257D&request_id=165932733816781647510270&biz_id=0&utm_medium=distribute.pc_search_result.none-task-blog-2~all~sobaiduend~default-2-108616902-null-null.142^v37^control&utm_term=python%E7%94%98%E7%89%B9%E5%9B%BE&spm=1018.2226.3001.4449

# coding=utf-8
import matplotlib.pyplot as plt
import matplotlib.patches as mpatches
plt.rcParams['font.sans-serif'] = ['SimHei']  # 用来正常显示中文标签
plt.rcParams['axes.unicode_minus'] = False  # 用来正常显示负号
add=[[14,6,23],[18,7,35],[10,30,21],[18,5,30],[10,25,20],[12,35,20],[10,32,17],[10,20,16]]
left=[[0,14,20],[14,32,43],[32,42,78],[42,72,99],[60,77,129],[70,102,149],[82,137,169],[92,169,189]]
m = range(len(add))
n=range(len(add[0]))
color = ['b','g','r','y','c','m','k']
 
#画布设置，大小与分辨率
plt.figure(figsize=(20,8),dpi=80)
#barh-柱状图换向，循坏迭代-层叠效果
for i in m:
    for j in n:
        plt.barh(m[i]+1, add[i][j], left=left[i][j],color=color[j])
plt.title("流水加工甘特图")
labels =[''] *len(add[0])
for f in n:
    labels[f] = "工序%d"%(f+1)
#图例绘制
patches = [ mpatches.Patch(color=color[i], label="{:s}".format(labels[i]) ) for i in range(len(add[0])) ]
plt.legend(handles=patches,loc=4)
#XY轴标签
plt.xlabel("加工时间/s")
plt.ylabel("工件加工优先级")
#网格线，此图使用不好看，注释掉
#plt.grid(linestyle="--",alpha=0.5)
plt.show()