PEP8: continuation line over-indented for visual indent
A continuation line is indented farther than it should be for a visual indent.
Anti-pattern In this example, the string "World" is indented two spaces farther than it should be.
print("Python", ("Hello",
"World"))
Best practice
print("Python", ("Hello",
"World"))
reference: https://www.flake8rules.com/rules/E127.html
The line-extending backslash has the issue of having trailing whitespace that can break your code. This is a popular fix and is PEP8-compliant:
if (first_index < 0 or
second_index > self._number_of_plates - 1):