Some briefly describe me what is the work of return "\n".join([self.cont,line,other.cont])?

Question

class SpecialString:
def __init__(self, cont):
self.cont = cont

def __truediv__(self, other):
line = "=" * len(other.cont)
return "\n".join([self.cont, line, other.cont])

spam = SpecialString("spam")
hello = SpecialString("Hello world!")
print(spam / hello)

Answer 1

Here return keyword is basically returning a value of __truediv__
join method of the string is used to join two strings.
self.cont is spam variable string, line is
= and number of = is equal to your other.cont length and other.cont is hello variable string.

and then print function giving output on the console.

Answer 2

The the .join joins the list into a string, and with the "\n", it is saying that for every element, join it and add the \n escape character.