def print_package_versions(self):
variants = self.context.get_tool_variants(self.tool_name)<EOL>if variants:<EOL><INDENT>if len(variants) > <NUM_LIT:1>:<EOL><INDENT>self._print_conflicting(variants)<EOL>return <NUM_LIT:1><EOL><DEDENT>else:<EOL><INDENT>from rez.packages_ import iter_packages<EOL>variant = next(iter(variants))<EOL>it = iter_packages(name=variant.name)<EOL>rows = []<EOL>colors = []<EOL>for pkg in sorted(it, key=lambda x: x.version, reverse=True):<EOL><INDENT>if pkg.version == variant.version:<EOL><INDENT>name = "<STR_LIT>" % pkg.qualified_name<EOL>col = heading<EOL><DEDENT>else:<EOL><INDENT>name = "<STR_LIT>" % pkg.qualified_name<EOL>col = local if pkg.is_local else None<EOL><DEDENT>label = "<STR_LIT>" if pkg.is_local else "<STR_LIT>"<EOL>rows.append((name, pkg.path, label))<EOL>colors.append(col)<EOL><DEDENT>_pr = Printer()<EOL>for col, line in zip(colors, columnise(rows)):<EOL><INDENT>_pr(line, col)<EOL><DEDENT><DEDENT><DEDENT>return <NUM_LIT:0><EOL>
Print a list of versions of the package this tool comes from, and
        indicate which version this tool is from.