how to check for a substring in python

>>> str = "Messi is the best soccer player"
>>> "soccer" in str
True
>>> "football" in str
False

def find_string(string,sub_string):
	return string.find(sub_string)
#.find() also accounts for multiple occurence of the substring in the given string

type('hello world') == str
# output: True

type(10) == str
# output: False

def is_value_in_string(value: str, the_string: str):
    return value in the_string.lower()

string contains, match