def normalize_axes(df, sample_axis, feature_axis):
    """Tests and transposes DataFrame to sample * feature format.
    
    Checks to make sure a user's axes inputs are 
    properly formatted. Flips a DF to put samples in
    index and features in columns.

    Arguments:
        df: dataset
        sample_axis: axis containing samples (0, 1)
        feature_axis: axis containing features (0,1)

    Returns: 
        DataFrame as samples * features
    
    """
    if sample_axis == 1 and feature_axis == 0:
        df = df.T
    elif sample_axis != 0 and feature_axis != 1:
        raise Exception('Invalid axis! Should be 0 or 1')
    return df