Openpyxl charts getting corrupted on export

[Himanshi verma]

Hi All,

I am facing the issue where when iam exporting charts into png , on or two charts are getting exported into corrupt images 
PFA the code section , and also the charts in sheet Sheet that Iam trying to export. 

I am not sure if it is because of some special character like . in the legend because only once it got saved .