Formats Python code to conform to the PEP 8 style guide.

def fix_code(code, directory):
    """Formats Python code to conform to the PEP 8 style guide.

    """
    if not black:
        raise Fault("black not installed", code=400)

    try:
        if parse_version(black.__version__) < parse_version("19.0"):
            reformatted_source = black.format_file_contents(
                src_contents=code, line_length=black.DEFAULT_LINE_LENGTH, fast=False
            )
        else:
            fm = black.FileMode()
            reformatted_source = black.format_file_contents(
                src_contents=code, fast=False, mode=fm
            )
        return reformatted_source
    except black.NothingChanged:
        return code
    except Exception as e:
        raise Fault("Error during formatting: {}".format(e), code=400)