def expand(self, indent_size: int) -> Iterable['_Line']:
    'Expand this line by adding children on their own line.'
    node = self.node
    assert (node is not None)
    whitespace = self.whitespace
    assert node.children
    if node.key_repr:
        (yield _Line(text=f'{node.key_repr}{node.key_separator}{node.open_brace}', whitespace=whitespace))
    else:
        (yield _Line(text=node.open_brace, whitespace=whitespace))
    child_whitespace = (self.whitespace + (' ' * indent_size))
    tuple_of_one = (node.is_tuple and (len(node.children) == 1))
    for child in node.children:
        separator = (',' if tuple_of_one else child.separator)
        line = _Line(node=child, whitespace=child_whitespace, suffix=separator)
        (yield line)
    (yield _Line(text=node.close_brace, whitespace=whitespace, suffix=(',' if (tuple_of_one and (not self.is_root)) else node.separator)))
Expand this line by adding children on their own line.
def expand(self, indent_size: int) -> Iterable['_Line']:
    
    node = self.node
    assert (node is not None)
    whitespace = self.whitespace
    assert node.children
    if node.key_repr:
        (yield _Line(text=f'{node.key_repr}{node.key_separator}{node.open_brace}', whitespace=whitespace))
    else:
        (yield _Line(text=node.open_brace, whitespace=whitespace))
    child_whitespace = (self.whitespace + (' ' * indent_size))
    tuple_of_one = (node.is_tuple and (len(node.children) == 1))
    for child in node.children:
        separator = (',' if tuple_of_one else child.separator)
        line = _Line(node=child, whitespace=child_whitespace, suffix=separator)
        (yield line)
    (yield _Line(text=node.close_brace, whitespace=whitespace, suffix=(',' if (tuple_of_one and (not self.is_root)) else node.separator)))