The r prefix on strings stands for “raw strings”.
Standard strings use backslash for escape characters:
“\n” is a newline, not backslash-n
“\t” is a tab, not backslash-t
“\u03C0” is the Greek letter pi, π, not backslash-u-zero-three-c-zero
and so forth. If you want to use backslashes in Windows pathnames, you
need to escape them by doubling:
wbkName = '\\AA\\chart.xlsx'
Alternatively, you can use raw strings, which switches off almost all
of the escape character processing:
wbkName = r'\AA\chart.xlsx'
or finally, and this is generally the recommended way, you can just use
forward slashes, since Windows will accept them as well:
wbkName = '/AA/chart.xlsx'