def find_nb_genes(data):
    """
    Finds the indices of all genes in the dataset that have
    a mean < 0.9 variance. Returns an array of booleans.
    """
    data_means = data.mean(1)
    data_vars = data.var(1)
    nb_indices = data_means < 0.9*data_vars
    return nb_indices
Finds the indices of all genes in the dataset that have
    a mean < 0.9 variance. Returns an array of booleans.