What should I do, when I have e.g. this line:
full_path = "https://www.google.cz/search?q=" + website_keywords # google link url
Flake8 reports me, that characters in line are above 79 max. length. What should I do with comment then, when PEP 8 says that inline-comment should be on the same line with particular statement.
It's usually fine to put a comment like that above the line:
# google link url
full_path = "https://www.google.cz/search?q=" + website_keywords
By the way, as of this writing, PEP 8 says that the line limit for comments is only 72.
For flowing long blocks of text with fewer structural restrictions (docstrings or comments), the line length should be limited to 72 characters.
...
Some teams strongly prefer a longer line length. For code maintained exclusively or primarily by a team that can reach agreement on this issue, it is okay to increase the nominal line length from 80 to 100 characters (effectively increasing the maximum length to 99 characters), provided that comments and docstrings are still wrapped at 72 characters.
It's not clear if that applies to inline comments, since they're not "long blocks of text", but PEP 8 also says,
Inline comments are unnecessary and in fact distracting if they state the obvious.
You might consider removing that comment altogether. The fact that it's a Google URL is kind of obvious considering that the string contains "google" in it.
There is one case where the comment really does have to be on the same line as what it's commenting about--PEP-484 type comments. In that case, you use parentheses:
full_path = (
"https://www.google.cz/search?q=" + website_keywords
) # type: str