def assert_legal_arguments(kwargs):
    """Assert that PrettyPrinter arguments are correct.

    Raises
    ------
    ValueError
        In case there are unknown arguments or a single layer is mapped to more than one aesthetic.
    """
    seen_layers = set()
    for k, v in kwargs.items():
        if k not in LEGAL_ARGUMENTS:
            raise ValueError('Illegal argument <{0}>!'.format(k))
        if k in AESTHETICS:
            if v in seen_layers:
                raise ValueError('Layer <{0}> mapped for more than a single aesthetic!'.format(v))
            seen_layers.add(v)
        if k in VALUES:
            if not isinstance(v, six.string_types) and not isinstance(v, list):
                raise ValueError('Value <{0}> must be either string or list'.format(k))
            if isinstance(v, list):
                if len(v) == 0:
                    raise ValueError('Rules cannot be empty list')
                for rule_matcher, rule_value in v:
                    if not isinstance(rule_matcher, six.string_types) or not isinstance(rule_value, six.string_types):
                        raise ValueError('Rule tuple elements must be strings')
def assert_legal_arguments ( kwargs ) : seen_layers = set ( ) for k , v in kwargs . items ( ) : if k not in LEGAL_ARGUMENTS : raise ValueError ( 'Illegal argument <{0}>!' . format ( k ) ) if k in AESTHETICS : if v in seen_layers : raise ValueError ( 'Layer <{0}> mapped for more than a single aesthetic!' . format ( v ) ) seen_layers . add ( v ) if k in VALUES : if not isinstance ( v , six . string_types ) and not isinstance ( v , list ) : raise ValueError ( 'Value <{0}> must be either string or list' . format ( k ) ) if isinstance ( v , list ) : if len ( v ) == 0 : raise ValueError ( 'Rules cannot be empty list' ) for rule_matcher , rule_value in v : if not isinstance ( rule_matcher , six . string_types ) or not isinstance ( rule_value , six . string_types ) : raise ValueError ( 'Rule tuple elements must be strings' )
Assert that PrettyPrinter arguments are correct.

    Raises
    ------
    ValueError
        In case there are unknown arguments or a single layer is mapped to more than one aesthetic.