Finding a Sub-String in a Main String (By Matching Positions of Sub-String)

def substrinstr(str1, str2):
    T1 = ()
    L1 = list(str2)


    for i in str1:
        if any(L1):
            if (i.lower() == L1[0]):
                T1 += (i,)
                del L1[0]
    else:
        L1 = list(str2)

        if T1 == tuple(L1):
            return "The Sub-String is Present in the String..."
        else:
            return "The Sub-String is NOT Present in the String..."

str1 = input("Enter the Full String : ")
str2 = input("Enter the Sub-String to be searched for in the String : ")
val = substrinstr(str1, str2)
print(val)