Function _safe_add_trailing_comma

src/black/linegen.py:1350–1359

(safe: bool, delimiter_priority: int, line: Line)

def _safe_add_trailing_comma(safe: bool, delimiter_priority: int, line: Line) -> Line:
    if (
        safe
        and delimiter_priority == COMMA_PRIORITY
        and line.leaves[-1].type != token.COMMA
        and line.leaves[-1].type != STANDALONE_COMMENT
    ):
        new_comma = Leaf(token.COMMA, ",")
        line.append(new_comma)
    return line


MIGRATE_COMMENT_DELIMITERS = {STRING_PRIORITY, COMMA_PRIORITY}