run black on test_source_multiline_block.py
run black on test_source_multiline_block.py

pfctdayelise/pytest,nicoddemus/pytest,The-Compiler/pytest,tomviner/pytest,nicoddemus/pytest,txomon/pytest,Akasurde/pytest,hackebrot/pytest,RonnyPfannschmidt/pytest,alfredodeza/pytest,tomviner/pytest,The-Compiler/pytest,pytest-dev/pytest,ddboline/pytest,davidszotten/pytest,markshao/pytest