COSMIT remove unecessary ravel
ENH remove unecessary function call
ENH remove _is_1d and _check_1d_array thanks to @GaelVaroquaux
ENH use squeeze instead of ravel
flake8
COSMIT + TST quieter tests
ENH raise ValueError with row vector if multilabel or multioutput is not supported
TST remove debugging print
ENH being less permissive thanks to @jnothman
FIX TST with multilabel helpers