import xlwings as xw

#Function to copy from one cell to another
def TestConnectionPython():
    
    #Make a connection to the calling Excel file
    wb = xw.Book.caller()
    
    # Store the main sheet location
    MainSheet = wb.sheets['Main']

    # Store the content of the named cell "Copy_Test"
    CopyTestValue = MainSheet.range('Copy_Test').value

    # Output the data just to make sure it all works
    MainSheet.range('Paste_Test').value = CopyTestValue