Global variables not working in script reports

Hi All,

When i was running script reports, i’m facing problem with the global variables. Not able to access global variables out of execute method(in production v11.1.13).

I have code below format:
def execute(filters=None):
global summary_data
summary_data = []
summary_data.append(“ERPNext”)

@frappe.whitelist()
def fetch_data():
print summary_data
return summary_data

Thanks,
Ragh.