demo_string_escape_error.py:
txt = "We are the so-called "Vikings" from the north." #You will get an error if you use double quotes inside a string that are surrounded by double quotes:
C:\Users\My Name>python demo_string_escape_error.py
File "demo_string_escape_error.py", line 1
txt = "We are the so-called "Vikings" from the north."
^
SyntaxError: invalid syntax