How to use the parso.python.tree.Flow function in parso

def get_statement_of_position(node, pos):
    for c in node.children:
        if c.start_pos <= pos <= c.end_pos:
            if c.type not in ('decorated', 'simple_stmt', 'suite') \
                    and not isinstance(c, (tree.Flow, tree.ClassOrFunc)):
                return c
            else:
                try:
                    return get_statement_of_position(c, pos)
                except AttributeError:
                    pass  # Must be a non-scope
    return None

def _analyse_non_prefix(self, leaf):
        typ = leaf.type
        if typ == 'name' and leaf.value in ('l', 'O', 'I'):
            if leaf.is_definition():
                message = "Do not define %s named 'l', 'O', or 'I' one line"
                if leaf.parent.type == 'class' and leaf.parent.name == leaf:
                    self.add_issue(leaf, 742, message % 'classes')
                elif leaf.parent.type == 'function' and leaf.parent.name == leaf:
                    self.add_issue(leaf, 743, message % 'function')
                else:
                    self.add_issuadd_issue(741, message % 'variables', leaf)
        elif leaf.value == ':':
            if isinstance(leaf.parent, (Flow, Scope)) and leaf.parent.type != 'lambdef':
                next_leaf = leaf.get_next_leaf()
                if next_leaf.type != 'newline':
                    if leaf.parent.type == 'funcdef':
                        self.add_issue(next_leaf, 704, 'Multiple statements on one line (def)')
                    else:
                        self.add_issue(next_leaf, 701, 'Multiple statements on one line (colon)')
        elif leaf.value == ';':
            if leaf.get_next_leaf().type in ('newline', 'endmarker'):
                self.add_issue(leaf, 703, 'Statement ends with a semicolon')
            else:
                self.add_issue(leaf, 702, 'Multiple statements on one line (semicolon)')
        elif leaf.value in ('==', '!='):
            comparison = leaf.parent
            index = comparison.children.index(leaf)
            left = comparison.children[index - 1]
            right = comparison.children[index + 1]

    @property
    def annotation(self):
        """
        Returns `None`, lambdas don't have annotations.
        """
        return None

    def __repr__(self):
        return "<%s@%s>" % (self.__class__.__name__, self.start_pos)


class Flow(PythonBaseNode):
    __slots__ = ()


class IfStmt(Flow):
    type = 'if_stmt'
    __slots__ = ()

    def get_test_nodes(self):
        """
        E.g. returns all the `test` nodes that are named as x, below:

            if x:
                pass
            elif x:
                pass
        """
        for i, c in enumerate(self.children):
            if c in ('elif', 'if'):
                yield self.children[i + 1]

def get_statement_of_position(node, pos):
    for c in node.children:
        if c.start_pos <= pos <= c.end_pos:
            if c.type not in ('decorated', 'simple_stmt', 'suite') \
                    and not isinstance(c, (tree.Flow, tree.ClassOrFunc)):
                return c
            else:
                try:
                    return get_statement_of_position(c, pos)
                except AttributeError:
                    pass  # Must be a non-scope
    return None

children = [child]
                    if child.type == 'simple_stmt':
                        # Remove the newline.
                        children = child.children[:-1]

                    found_docstring = False
                    for c in children:
                        if c.type == 'string' and not found_docstring:
                            continue
                        found_docstring = True

                        if c.type == 'expr_stmt' and \
                                all(_is_magic_name(n) for n in c.get_defined_names()):
                            continue

                        if c.type in _IMPORT_TYPES or isinstance(c, Flow):
                            continue

                        self.add_issue(node, 402, 'Module level import not at top of file')
                        break
                    else:
                        continue
                    break

        implicit_indentation_possible = typ in _IMPLICIT_INDENTATION_TYPES
        in_introducer = typ in _SUITE_INTRODUCERS
        if in_introducer:
            self._in_suite_introducer = True
        elif typ == 'suite':
            if self._indentation_tos.type == IndentationTypes.BACKSLASH:
                self._indentation_tos = self._indentation_tos.parent

else:
                    return check_node

    def is_node_after_else(self, node):
        """
        Checks if a node is defined after `else`.
        """
        for c in self.children:
            if c == 'else':
                if node.start_pos > c.start_pos:
                    return True
        else:
            return False


class WhileStmt(Flow):
    type = 'while_stmt'
    __slots__ = ()


class ForStmt(Flow):
    type = 'for_stmt'
    __slots__ = ()

    def get_testlist(self):
        """
        Returns the input node ``y`` from: ``for x in y:``.
        """
        return self.children[3]

    def get_defined_names(self, include_setitem=False):
        return _defined_names(self.children[1], include_setitem)

# Check name
            key, lazy_context = args[1]
            names = list(lazy_context.infer())
            assert len(names) == 1 and isinstance(names[0], CompiledObject)
            assert names[0].obj == payload[1].value

            # Check objects
            key, lazy_context = args[0]
            objects = lazy_context.infer()
            return payload[0] in objects
        except AssertionError:
            return False

    obj = jedi_name
    while obj is not None and not isinstance(obj, (tree.Function, tree.Class)):
        if isinstance(obj, tree.Flow):
            # try/except catch check
            if obj.type == 'try_stmt' and check_try_for_except(obj, exception):
                return True
            # hasattr check
            if exception == AttributeError and obj.type in ('if_stmt', 'while_stmt'):
                if check_hasattr(obj.children[1], obj.children[3]):
                    return True
        obj = obj.parent

    return False

def get_flow_scope_node(module_node, position):
    node = module_node.get_leaf_for_position(position, include_prefixes=True)
    while not isinstance(node, (tree.Scope, tree.Flow)):
        node = node.parent

    return node

def get_parent_scope(node, include_flows=False):
    """
    Returns the underlying scope.
    """
    scope = node.parent
    if scope is None:
        return None  # It's a module already.

    while True:
        if is_scope(scope) or include_flows and isinstance(scope, tree.Flow):
            if scope.type in ('classdef', 'funcdef', 'lambdef'):
                index = scope.children.index(':')
                if scope.children[index].start_pos >= node.start_pos:
                    if node.parent.type == 'param' and node.parent.name == node:
                        pass
                    elif node.parent.type == 'tfpdef' and node.parent.children[0] == node:
                        pass
                    else:
                        scope = scope.parent
                        continue
            return scope
        scope = scope.parent
    return scope

class ForStmt(Flow):
    type = 'for_stmt'
    __slots__ = ()

    def get_testlist(self):
        """
        Returns the input node ``y`` from: ``for x in y:``.
        """
        return self.children[3]

    def get_defined_names(self, include_setitem=False):
        return _defined_names(self.children[1], include_setitem)


class TryStmt(Flow):
    type = 'try_stmt'
    __slots__ = ()

    def get_except_clause_tests(self):
        """
        Returns the ``test`` nodes found in ``except_clause`` nodes.
        Returns ``[None]`` for except clauses without an exception given.
        """
        for node in self.children:
            if node.type == 'except_clause':
                yield node.children[1]
            elif node == 'except':
                yield None


class WithStmt(Flow):