Use the isinstance built-in function to check if the variable is a string in Python. It takes two arguments, the first is variable, and the second is the type you want to check for.
isinstance(Var, Data_Type)
Python checks if the variable is a string example
Simple example code, The first parameter will be given a variable, and the second is the data type string.
var = "String"
print(isinstance(var, str))
Output:

Another Example
Uses the type built-in function to see if the type of your variable is str.
var = "String"
if type(var) == str:
print("String type")
Output: String type
Do comment if you have any questions or suggestions on this Python var string topic.
Note: IDE: PyCharm 2021.3.3 (Community Edition)
Windows 10
Python 3.10.1
All Python Examples are in Python 3, so Maybe its different from python 2 or upgraded versions.