Your result: "true" and Right result: true ?

My Code:

def checkio(matrix):
    #replace this for solution

    i=0
    for i in range(3):
        if matrix[i][i] == matrix[i+1][i+1]: 
            #val = 'true1'

        if matrix[i][i] == matrix[i+1][i]: 
            return 'true'
        else: 
            return 'false'

If i check the code, I get the following:

          Your result: "true" 
          Right result: true

What I am doing wrong ?

Thanks

if __name__ == '__main__':
    #These "asserts" using only for self-checking and not necessary for auto-testing
    assert checkio([
        [1, 2, 1, 1],
        [1, 1, 4, 1],
        [1, 3, 1, 6],
        [1, 7, 2, 5]
    ]) == True, "Vertical"
    assert checkio([
        [7, 1, 4, 1],
        [1, 2, 5, 2],
        [3, 4, 1, 3],
        [1, 1, 8, 1]
    ]) == False, "Nothing here"
    assert checkio([
        [2, 1, 1, 6, 1],
        [1, 3, 2, 1, 1],
        [4, 1, 1, 3, 1],
        [5, 5, 5, 5, 5],
        [1, 1, 3, 1, 1]
    ]) == True, "Long Horizontal"
    assert checkio([
        [7, 1, 1, 8, 1, 1],
        [1, 1, 7, 3, 1, 5],
        [2, 3, 1, 2, 5, 1],
        [1, 1, 1, 5, 1, 4],
        [4, 6, 5, 1, 3, 1],
        [1, 1, 9, 1, 2, 1]
    ]) == True, "Diagonal"