How to use the parso.python.errors.SyntaxRule function in parso

else:
                            arg_set.add(first.value)
            else:
                if kw_unpacking_only:
                    # f(**x, y)
                    message = "positional argument follows keyword argument unpacking"
                    self.add_issue(argument, message=message)
                elif kw_only:
                    # f(x=2, y)
                    message = "positional argument follows keyword argument"
                    self.add_issue(argument, message=message)


@ErrorFinder.register_rule(type='parameters')
@ErrorFinder.register_rule(type='lambdef')
class _ParameterRule(SyntaxRule):
    # def f(x=3, y): pass
    message = "non-default argument follows default argument"

    def is_issue(self, node):
        param_names = set()
        default_only = False
        for p in _iter_params(node):
            if p.name.value in param_names:
                message = "duplicate argument '%s' in function definition"
                self.add_issue(p.name, message=message % p.name.value)
            param_names.add(p.name.value)

            if p.default is None and not p.star_count:
                if default_only:
                    return True
            else:

else:
                    message = 'expression cannot contain assignment, perhaps you meant "=="?'
            else:
                # f(+x=1)
                if self._normalizer.version < (3, 8):
                    message = "keyword can't be an expression"
                else:
                    message = 'expression cannot contain assignment, perhaps you meant "=="?'
            self.add_issue(first, message=message)

        if _is_argument_comprehension(node) and node.parent.type == 'classdef':
            self.add_issue(node, message='invalid syntax')


@ErrorFinder.register_rule(type='nonlocal_stmt')
class _NonlocalModuleLevelRule(SyntaxRule):
    message = "nonlocal declaration not allowed at module level"

    def is_issue(self, node):
        return self._normalizer.context.parent_context is None


@ErrorFinder.register_rule(type='arglist')
class _ArglistRule(SyntaxRule):
    @property
    def message(self):
        if self._normalizer.version < (3, 7):
            return "Generator expression must be parenthesized if not sole argument"
        else:
            return "Generator expression must be parenthesized"

    def is_issue(self, node):

def is_issue(self, node):
        if node.children[-1] == ',' and node.parent.children[-1] != ')':
            return True


@ErrorFinder.register_rule(type='import_from')
class _ImportStarInFunction(SyntaxRule):
    message = "import * only allowed at module level"

    def is_issue(self, node):
        return node.is_star_import() and self._normalizer.context.parent_context is not None


@ErrorFinder.register_rule(type='import_from')
class _FutureImportRule(SyntaxRule):
    message = "from __future__ imports must occur at the beginning of the file"

    def is_issue(self, node):
        if _is_future_import(node):
            if not _is_future_import_first(node):
                return True

            for from_name, future_name in node.get_paths():
                name = future_name.value
                allowed_futures = list(ALLOWED_FUTURES)
                if self._normalizer.version >= (3, 5):
                    allowed_futures.append('generator_stop')
                if self._normalizer.version >= (3, 7):
                    allowed_futures.append('annotations')
                if name == 'braces':
                    self.add_issue(node, message="not a chance")

if first_is_bytes != self._is_bytes_literal(string):
                    return True


@ErrorFinder.register_rule(type='import_as_names')
class _TrailingImportComma(SyntaxRule):
    # e.g. from foo import a,
    message = "trailing comma not allowed without surrounding parentheses"

    def is_issue(self, node):
        if node.children[-1] == ',' and node.parent.children[-1] != ')':
            return True


@ErrorFinder.register_rule(type='import_from')
class _ImportStarInFunction(SyntaxRule):
    message = "import * only allowed at module level"

    def is_issue(self, node):
        return node.is_star_import() and self._normalizer.context.parent_context is not None


@ErrorFinder.register_rule(type='import_from')
class _FutureImportRule(SyntaxRule):
    message = "from __future__ imports must occur at the beginning of the file"

    def is_issue(self, node):
        if _is_future_import(node):
            if not _is_future_import_first(node):
                return True

            for from_name, future_name in node.get_paths():

return node.get_next_leaf()

    def is_issue(self, node):
        error = node.get_next_leaf().type != 'error_leaf'
        if (
            error
            and _any_fstring_error(self._normalizer.version, node)
        ):
            self.add_issue(node, message=self.fstring_message)
        else:
            # Error leafs will be added later as an error.
            return error


@ErrorFinder.register_rule(value='await')
class _AwaitOutsideAsync(SyntaxRule):
    message = "'await' outside async function"

    def is_issue(self, leaf):
        return not self._normalizer.context.is_async_funcdef()

    def get_error_node(self, node):
        # Return the whole await statement.
        return node.parent


@ErrorFinder.register_rule(value='break')
class _BreakOutsideLoop(SyntaxRule):
    message = "'break' outside loop"

    def is_issue(self, leaf):
        in_loop = False

in_loop = True
            if block.type == 'try_stmt':
                last_block = block.children[-3]
                if (
                    last_block == "finally"
                    and leaf.start_pos > last_block.start_pos
                    and self._normalizer.version < (3, 8)
                ):
                    self.add_issue(leaf, message=self.message_in_finally)
                    return False  # Error already added
        if not in_loop:
            return True


@ErrorFinder.register_rule(value='from')
class _YieldFromCheck(SyntaxRule):
    message = "'yield from' inside async function"

    def get_node(self, leaf):
        return leaf.parent.parent  # This is the actual yield statement.

    def is_issue(self, leaf):
        return leaf.parent.type == 'yield_arg' \
            and self._normalizer.context.is_async_funcdef()


@ErrorFinder.register_rule(type='name')
class _NameChecks(SyntaxRule):
    message = 'cannot assign to __debug__'
    message_none = 'cannot assign to None'

    def is_issue(self, leaf):

@ErrorFinder.register_rule(value='**')
class _StarStarCheck(SyntaxRule):
    # e.g. {**{} for a in [1]}
    # TODO this should probably get a better end_pos including
    #      the next sibling of leaf.
    message = "dict unpacking cannot be used in dict comprehension"

    def is_issue(self, leaf):
        if leaf.parent.type == 'dictorsetmaker':
            comp_for = leaf.get_next_sibling().get_next_sibling()
            return comp_for is not None and comp_for.type in _COMP_FOR_TYPES


@ErrorFinder.register_rule(value='yield')
@ErrorFinder.register_rule(value='return')
class _ReturnAndYieldChecks(SyntaxRule):
    message = "'return' with value in async generator"
    message_async_yield = "'yield' inside async function"

    def get_node(self, leaf):
        return leaf.parent

    def is_issue(self, leaf):
        if self._normalizer.context.node.type != 'funcdef':
            self.add_issue(self.get_node(leaf), message="'%s' outside function" % leaf.value)
        elif self._normalizer.context.is_async_funcdef() \
                and any(self._normalizer.context.node.iter_yield_exprs()):
            if leaf.value == 'return' and leaf.parent.type == 'return_stmt':
                return True
            elif leaf.value == 'yield' \
                    and leaf.get_next_leaf() != 'from' \
                    and self._normalizer.version == (3, 5):

self.add_issue(name, message=self.message_conversion)

        format_spec = fstring_expr.children[-2]
        if format_spec.type == 'fstring_format_spec':
            self._check_format_spec(format_spec, depth + 1)

    def is_issue(self, fstring):
        self._check_fstring_contents(fstring.children[1:-1])

    def _check_fstring_contents(self, children, depth=0):
        for fstring_content in children:
            if fstring_content.type == 'fstring_expr':
                self._check_fstring_expr(fstring_content, depth)


class _CheckAssignmentRule(SyntaxRule):
    def _check_assignment(self, node, is_deletion=False, is_namedexpr=False, is_aug_assign=False):
        error = None
        type_ = node.type
        if type_ == 'lambdef':
            error = 'lambda'
        elif type_ == 'atom':
            first, second = node.children[:2]
            error = _get_comprehension_type(node)
            if error is None:
                if second.type == 'dictorsetmaker':
                    if self._normalizer.version < (3, 8):
                        error = 'literal'
                    else:
                        if second.children[1] == ':':
                            error = 'dict display'
                        else:

def is_issue(self, leaf):
        if self._normalizer.context.node.type != 'funcdef':
            self.add_issue(self.get_node(leaf), message="'%s' outside function" % leaf.value)
        elif self._normalizer.context.is_async_funcdef() \
                and any(self._normalizer.context.node.iter_yield_exprs()):
            if leaf.value == 'return' and leaf.parent.type == 'return_stmt':
                return True
            elif leaf.value == 'yield' \
                    and leaf.get_next_leaf() != 'from' \
                    and self._normalizer.version == (3, 5):
                self.add_issue(self.get_node(leaf), message=self.message_async_yield)


@ErrorFinder.register_rule(type='strings')
class _BytesAndStringMix(SyntaxRule):
    # e.g. 's' b''
    message = "cannot mix bytes and nonbytes literals"

    def _is_bytes_literal(self, string):
        if string.type == 'fstring':
            return False
        return 'b' in string.string_prefix.lower()

    def is_issue(self, node):
        first = node.children[0]
        # In Python 2 it's allowed to mix bytes and unicode.
        if self._normalizer.version >= (3, 0):
            first_is_bytes = self._is_bytes_literal(first)
            for string in node.children[1:]:
                if first_is_bytes != self._is_bytes_literal(string):
                    return True

if self._normalizer.version >= (3, 5):
                    allowed_futures.append('generator_stop')
                if self._normalizer.version >= (3, 7):
                    allowed_futures.append('annotations')
                if name == 'braces':
                    self.add_issue(node, message="not a chance")
                elif name == 'barry_as_FLUFL':
                    m = "Seriously I'm not implementing this :) ~ Dave"
                    self.add_issue(node, message=m)
                elif name not in allowed_futures:
                    message = "future feature %s is not defined" % name
                    self.add_issue(node, message=message)


@ErrorFinder.register_rule(type='star_expr')
class _StarExprRule(SyntaxRule):
    message_iterable_unpacking = "iterable unpacking cannot be used in comprehension"
    message_assignment = "can use starred expression only as assignment target"

    def is_issue(self, node):
        if node.parent.type == 'testlist_comp':
            # [*[] for a in [1]]
            if node.parent.children[1].type in _COMP_FOR_TYPES:
                self.add_issue(node, message=self.message_iterable_unpacking)
        if self._normalizer.version <= (3, 4):
            n = search_ancestor(node, 'for_stmt', 'expr_stmt')
            found_definition = False
            if n is not None:
                if n.type == 'expr_stmt':
                    exprs = _get_expr_stmt_definition_exprs(n)
                else:
                    exprs = _get_for_stmt_definition_exprs(n)