Type matrix and display smaller/larger and their positions

Question

I made the following code that generates the matrix with random values as the dimensions are passed, and brings the result of the lowest value and its position and the highest value and its position. Instead of passing the dimensions of the matrix and it being generated, I would like to type each matrix value, separated by blank spaces. If the first line is empty, display the message that it is empty. Entering the values of the matrix, display the final typed matrix and its respective smallest and largest value and its positions.

Matrix size is not set, if it is 4x4 for example. You enter the amount you want.

Currently the code is like this:

def generate(numLins, numCols, mn, mx):
    from random import randint
    values = [None] * numLins
    for i in range(numLins):
        values[i] = [0] * numCols
        for j in range(numCols):
            values[i][j] = randint(mn, mx)
    return values


def reveal(values, linMn, linMx, colMn, colMx):
    for i in range(linMn, linMx):
        for j in range(colMn, colMx):
            print(values[i][j], end=" ")
        print()
    print()
    return None

def localizaCelulaComMaiorValor(vals):
    resp = (0, 0)
    for lin in range(len(vals)):
        for col in range(len(vals[lin])):
            if vals[lin][col] > vals[resp[0]][resp[1]]:
                resp = (lin, col)
    return resp


def localizaCelulaComMenorValor(vals):
    resp = (0, 0)
    for lin in range(len(vals)):
        for col in range(len(vals[lin])):
            if vals[lin][col] < vals[resp[0]][resp[1]]:
                resp = (lin, col)
    return resp


print("Dimensões da Matriz:")
dimensoes = input().split()
numLins = int(dimensoes[0])
numCols = int(dimensoes[1])


valores = generate(numLins, numCols, 10, 99)
reveal(valores, 0, numLins, 0, numCols)


ondeMaior = localizaCelulaComMaiorValor(valores)
print("Maior Valor:", valores[ondeMaior[0]][ondeMaior[1]], "na posição: (", ondeMaior[0], ",", ondeMaior[1], ")")

ondeMenor = localizaCelulaComMenorValor(valores)
print("Menor Valor:", valores[ondeMenor[0]][ondeMenor[1]], "na posição: (",ondeMenor[0],",",ondeMenor[1],")" )