説明/参照: https://www.splunk.com/en_us/blog/tips-and-tricks/search-commands-stats-chart-and-timechart.html

To create a macro that accepts arguments, you must include the number of arguments in parentheses at the end
of the macro name1. For example, my_macro(3) is a macro that accepts three arguments. The number of
arguments in the macro name must match the number of arguments in the definition1. Therefore, option A is
correct, while options B, C and D are incorrect.