fix nan error

kpi.py

 if __name__ == "__main__":
     kpi = dist()
     kpi_csv = pd.DataFrame([kpi])
-    kpi = kpi_csv.fillna(0)
+    kpi_csv = kpi_csv.fillna(0)
     kpi_csv.to_csv(os.path.join(file_path,'kpi.csv'))
-    put_kpi_to_db(kpi)
+    put_kpi_to_db(kpi_csv)