def load_mmprox(datafile, values='nrofimsi'):
    """
    Process raw Proximus datafile into a mobility matrix for either nrofimsi values or est_staytime values
    
    Input
    -----
    datafile: pandas.DataFrame
        loaded from load_datafile_proximus
    values: str
        Either 'nrofimsi' (visit counts) or 'est_staytime' (estimated staytime)
    
    Output
    ------
    mmprox: pandas.DataFrame
        pandas DataFrames with visit counts or estimated staytime between postal codes.
    """
    mmprox = datafile.pivot_table(values=values,
                                  index='mllp_postalcode',
                                  columns='postalcode').fillna(value=0)
    return mmprox