Invalid code generated by removing parens from Call node

[Zac-HD]

from libcst import *

attr = Attribute(
    value=List(elements=[]), attr=Name(value="append"),
    dot=Dot(whitespace_before=ParenthesizedWhitespace(
        first_line=TrailingWhitespace(newline=Newline()))
    ),
)
node = Call(func=attr, args=[Arg(value=Integer(value="1"))])

code = Module([]).code_for_node(node)
assert code == "[]\n.append(1)"
parse_module(code)  # error, invalid syntax!

I discovered this via an (inadequately tested) codemod in shed, which removed required parentheses around "fluent interface" call chains (as preferred by Black).

I can work around this in shed just by checking that the proposed replacement compiles, but it would be nice if (a) this was an immediate error, and (b) parens could take a MaybeSentinel to handle it automatically. Related to #287, #341.

[zsol]

This is a tricky one - it's unclear which node's responsibility should include validating the presence of these required parens.