Convergence of linear problems

[Capital2]

runBigm() says it does not converge for some linear problems like the ones in the tests.
when changing the M value to 10^10 the example converges.
find a nice algorithm to choose a good Big M ?

[Capital2]

Important!!!
["Max Z = x+5y","3x+4y<=6","x+3y>=2"] this one straight up gives up wrong output:
[('x2', 1.6666599999881626e-05, 1), ('x1', 1.99998, 0)]
expected output is x=0 y=1.5

ps: this problem was given by the last group