LGTM.com - false positive - XXX may be at an arbitrary position in the sanitized URL.

**Description of the false positive**

We got a warning that a string may be at an arbitrary position in the sanitized URL. After looking at the code and at the warning's explanation I can definitely understand the sentiment of the warning but it is a bit opinionated. Can't assume that every time there is such a check there is a vulnerability hidden.

For example in this code's case it checks if `infura.io` is in the URL (can have various permutations so not using `startswith`) and if it is we try to make it easier for the user by using a different querying range. There is no danger whatsoever if somehow there is infura.io in a non correct part of the url.

**URL to the alert on the project page on LGTM.com**

https://lgtm.com/projects/g/rotki/rotki/snapshot/67b7fedfc510b557a4ecd6d6d8c5bd32dbfeb2e6/files/rotkehlchen/chain/ethereum/manager.py?sort=name&dir=ASC&mode=heatmap#x11dc760fe6c8da89:1