def convert_sheets_to_df_dicts(excel):
    """
    Parses the input excel sheets into data frame
    :param excel: object that contains the input excel.
    returns sheet_dict: dictionary with sheet names as key and corresponding dataframe as value
    """
    sheet_dict = {}
    for sheet_name in excel.sheet_names:
        sheet_dict[sheet_name] = excel.parse(sheet_name)

    if 'LSTN_activation' not in sheet_dict or 'dvSTN_activation' not in sheet_dict or 'RSTN_activation' not in sheet_dict :
        raise KeyError()

    return sheet_dict