Binary String

def bincheck(string) :
    t = '01'
    #set counter to 0
    count = 0
    # looping through each character
    # of the string .
    for char in string :
        if char not in t :
            count = 1
            break
        else :
            pass
    if count :
        print("No, the string is not binary.")
    else :
        print("Yes, the string is binary.")
string = input("Enter string: ")
# function calling
bincheck(string)