e_non_expressed(df: pd.DataFrame, verbose: bool=False):
    &#34;&#34;&#34;
    Identifies and removes genes with mean 0 from the dataframe,
    i.e. non-expressed genes.
    
    Parameters
    ----------
    df : DataFrame
        Gene expression data, e.g. UMI counts.
    
    verbose : bool, optional (default: False)
        Print progress report.
    
    Returns
    -------
    df_filtered : DataFrame
        Filtered data with no genes with mean 0 expression across all cells.

    NOTE:
    * df form