PEP 484: Fixed typos, IOW, apply PEP8 inline comment space

[pzrq]

Fixed Typos

Link
"Similarly, there is no support for specifying callback signatures with a variable number of argument of a specific type."
Changed to:
arguments

Link
"I/O releated types:"
Changed to:
related

Replaced IOW -> In other words

Link

"... that's a subtype of C, not a special form. IOW, in the above example calling e.g. new_user(Union[BasicUser, ProUser]) is ..."
Changed to:
In other words

Reasoning

I'm reasonably sure IOW is intended to mean In other words (i.e. UrbanDictionary:IOW instead of one of Wikipedia:IOW) in this context, so have optimistically suggested this replacement.

See PEP 20: Explicit is better than implicit.

Applied PEP 8: Inline comments

(Note this occurred in many places, please review the diff or individual commits for details)
e.g.

        class AlsoBad:
-           x = None # type: List[T] # Also an error
+           x = None  # type: List[T] # Also an error
                     ^

Reasoning

• PEP8: "Inline comments should be separated by at least two spaces from the statement."

• Also, as noted in this PEP484 Type comments section, type comments should be at the start, and can then be followed by a comment, separated with a single space as it is a comment within a comment, i.e.

  # type: ignore # <comment or other marker>

---

@Mariatta @johnsonb2 Thank you for the inspiration in #914

[Mariatta]

Thanks for the PR. I think the typo fixes, like "in other words" and "repeated" are good improvements to the PEP, but not sure about the whitespace changes just for the sake of PEP 8. I'll leave it to PEP authors to decide and merge.

[gvanrossum]

Thanks! I approve of the changes, including the whitespace changes. (Technically, PEP 8 doesn't endorse lining up comments, but I think it looks better here. :-)