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Sankey graph not displaying outflow and target undefined

I created a Sankey graph from a dataframe using this SO squestion. but my target shows undefined when I hover the graph, my outflowing count also displays 0

below is my code and my dataframe.

# imports
import pandas as pd
import numpy as np
import plotly.graph_objs as go
from plotly.offline import download_plotlyjs, init_notebook_mode, plot, iplot
init_notebook_mode(connected=True)


# Retrieve data
df = df[['Label1','value','year']]
dmap = {'cs.AI':0,'cs.CC':1,'cs.CE':2,'cs.CG':3,'cs.CL':4,'cs.CR':5}
df['source'] = df['Label1'].map(dmap)
df.sort_values(by=["source"], inplace=True)
nodes_color = ['#a6cee3','#fdbf6f','#fb9a99','#e3a6ce','#a6e3da','#a6e3bd']
L = [6,7,8,9,10,11,12,13,15,16,17,18,19,20,21,22,23,24,25]
df['target'] = df.groupby('source').cumcount().map(dict(enumerate(L)))
label = list(df['Label1'].unique())
target = list(df['target'])
value = list(df['value'])
source = list(df['source'])
link_color = np.repeat(np.array(['#a6cee3','#fdbf6f','#fb9a99','#e3a6ce','#a6e3da','#a6e3bd'], dtype=object), 18).tolist()


# Sankey plot setup
data_trace = dict(
    type='sankey',
    domain = dict(
      x =  [0,1],
      y =  [0,1]
    ),
    orientation = "h",
    valueformat = ".0f",
    node = dict(
      pad = 20,
    # thickness = 30,
      line = dict(
        color = "black",
        width = 0
      ),
      label =  label,
      color = 
    ),
    link = dict(
      source = source,
      target = target,
      value = value,
      color = link_color,
  )
)

layout = dict(
        title = "Draw Sankey Diagram from dataframes",
    height = 772,
    font = dict(
      size = 10),)

fig = dict(data=[data_trace], layout=layout)
iplot(fig, validate=False)

my dataframe

      Label1  value   year
0   cs.AI   1.00    1990
1   cs.AI   0.20    1990
2   cs.AI   0.85    1990
3   cs.AI   0.99    1990
4   cs.AI   0.19    1990
5   cs.AI   0.87    1990
6   cs.CC   0.19    1990
7   cs.CC   1.00    1990
8   cs.CC   0.34    1990
9   cs.CC   0.50    1990
10  cs.CC   0.09    1990
11  cs.CC   0.67    1990
12  cs.CE   0.94    1990
13  cs.CE   0.63    1990
14  cs.CE   1.00    1990
15  cs.CE   0.61    1990
16  cs.CE   0.82    1990
17  cs.CE   0.17    1990
18  cs.CG   0.74    1990
19  cs.CG   0.95    1990
20  cs.CG   0.53    1990
21  cs.CG   1.00    1990
22  cs.CG   0.43    1990
23  cs.CG   0.10    1990
24  cs.CL   0.31    1990
25  cs.CL   0.27    1990
26  cs.CL   0.91    1990
27  cs.CL   0.21    1990
28  cs.CL   1.00    1990
29  cs.CL   0.12    1990
30  cs.CR   0.31    1990
31  cs.CR   0.18    1990
32  cs.CR   0.76    1990
33  cs.CR   0.35    1990
34  cs.CR   0.67    1990
35  cs.CR   1.00    1990
36  cs.AI   1.00    1991
37  cs.AI   0.55    1991
38  cs.AI   0.82    1991
39  cs.AI   0.05    1991
40  cs.AI   0.17    1991
41  cs.AI   0.83    1991
42  cs.CC   0.52    1991
43  cs.CC   1.00    1991
44  cs.CC   0.64    1991
45  cs.CC   1.00    1991
46  cs.CC   0.80    1991
47  cs.CC   0.21    1991
48  cs.CE   0.10    1991
49  cs.CE   0.58    1991
50  cs.CE   1.00    1991
51  cs.CE   0.01    1991
52  cs.CE   0.77    1991
53  cs.CE   0.19    1991
54  cs.CG   0.08    1991
55  cs.CG   0.21    1991
56  cs.CG   0.63    1991
57  cs.CG   1.00    1991
58  cs.CG   0.34    1991
59  cs.CG   0.60    1991
60  cs.CL   0.91    1991
61  cs.CL   0.33    1991
62  cs.CL   0.60    1991
63  cs.CL   0.57    1991
64  cs.CL   1.00    1991
65  cs.CL   0.37    1991
66  cs.CR   1.00    1991
67  cs.CR   0.28    1991
68  cs.CR   0.92    1991
69  cs.CR   0.47    1991
70  cs.CR   0.53    1991
71  cs.CR   1.00    1991
72  cs.AI   1.00    1992
73  cs.AI   0.79    1992
74  cs.AI   0.86    1992
75  cs.AI   0.30    1992
76  cs.AI   0.27    1992
77  cs.AI   0.91    1992
78  cs.CC   0.06    1992
79  cs.CC   1.00    1992
80  cs.CC   0.72    1992
81  cs.CC   0.44    1992
82  cs.CC   0.31    1992
83  cs.CC   0.75    1992
84  cs.CE   0.40    1992
85  cs.CE   0.07    1992
86  cs.CE   1.00    1992
87  cs.CE   0.88    1992
88  cs.CE   0.79    1992
89  cs.CE   0.03    1992
90  cs.CG   0.74    1992
91  cs.CG   0.91    1992
92  cs.CG   1.00    1992
93  cs.CG   1.00    1992
94  cs.CG   0.68    1992
95  cs.CG   0.22    1992
96  cs.CL   0.42    1992
97  cs.CL   0.03    1992
98  cs.CL   0.95    1992
99  cs.CL   0.17    1992
100 cs.CL   1.00    1992
101 cs.CL   0.28    1992
102 cs.CR   0.04    1992
103 cs.CR   0.30    1992
104 cs.CR   0.26    1992
105 cs.CR   0.80    1992
106 cs.CR   0.90    1992
107 cs.CR   1.00    1992

my Sankey graph.