def fill_NaN(df):
    """Fill NaN entries with proper empty values
     Type  : dtype: Fill with
     string: "0"  : ''
     float : "float64"
    """
    for key in df.columns:
        if df[key].dtype == 'O':
            df[key] = df[key].fillna('')
        elif df[key].dtype == 'float64':
            df[key] = df[key].fillna(0.0)
    return df
