prośba o krótki code review

Czy w miarę robię zgodnie ze sztuką?

Klasa ExcelTable zawiera pary klucz-wartość (duplikaty klucza akceptowalne), gdzie kluczem są wiersze tabelki z excela a wartością kolumny innej tabelka też z excela. Klasa obsługuje głównie wyciąganie kolumny z tabeli wartości o nr odpowiadającym nr zadanego wiersza z tabeli kluczy. Pozostałe klasy są pomocnicze.

class Request:

    def __init__(self, variable, code, period, currency):
        self.variable = variable
        self.code = code
        self.period = period
        self.currency = currency
                                                                           
    def __str__(self):
        return str(self.variable) + " " + str(self.code) + " " + str(self.period) + " " + str(self.currency)


class Result:

    def __init__(self):
        self.key = None
        self.values = None
        self.is_successfull = False

    def __str__(self):
        return str(self.is_successfull) + str(self.key) + "\n" + str(self.values)

.

class FindFun:

    __BASIC__ = lambda df, req: ((df.VariableName == req.variable)
                               & (df.Code== req.code)
                               & (df.Period== req.period)).tolist()

    __GROUP__ = lambda df, req: ((df.VariableName == req.variable)
                               & (df.Code.map(lambda x: x[:4]) == req.code[:4])
                               & (df.Period== req.period)).tolist()

.

class ExcelTable:
   
    def __init__(self, key, values):
    """
    i-row of `key` frame corresponds i-col of `values` frame
    """
        self.key = key
        self.values = self._init_values(values)

    def _init_values(self, v):
    """ 
    The name of the values' columns should be equal to key.VariableName if exists
    """
        v.columns = self.key.VariableName if "VariableName" in self.key.columns else pd.Index([])
        return v
   
    @staticmethod
    def create_empty():
        key = pd.DataFrame()
        values = pd.DataFrame(index=pd.Index(np.arange(START_YEAR, END_YEAR + 1)))
        values.index.names = ['Year']
        et = ExcelTable(key, values)
        return et
   
    def extrapolate(self):
    """
    Linear extrapolation of the values' last rows if they are NaN.
    """
        self.values = self.values.fillna(method='ffill')
        return self
   
    def get_key_by_idx(self, idx):
        return self.key.iloc[idx, :]

    def get_key_by_idx_first(self, idx):
        return self.get_values_by_idx(idx.index(True))
   
    def get_values_by_idx(self, idx):
        return self.values.iloc[:, idx]
   
    def get_values_by_idx_first(self, idx):
        return self.get_values_by_idx(idx.index(True))
                                                                       
    def find(self, request, find_fun = FindFun.__BASIC__):
        """
        Gets the only occurence for the found idx.
        Accepts only 1 found idx.
       
        Args:
            request: (Request)
            find_fun: (function) optional
           
        Returns:
            (Result)
        """
        found_idx = find_fun(self.key, request)
        if sum(found_idx) > 1:
            raise DuplicatedValues(
                "Found more then 1 value corresponding to " +
                request.variable + " " + request.code + " " + request.period +
                "Check for duplicated in the input file."
            )
        result = Result()
        if sum(found_idx) == 1:
            result.is_successfull = True
            result.key = get_key_by_idx(found_idx)
            result.values = get_values_by_idx(found_idx)
        return result
                                                                               
    def find_first(self, request, find_fun = FindFun.__GROUP__):
        """
        Gets the first occurence for the found idx.
        Accepts more than 1 found idxes.
       
        Args:
            request: (Request)
            find_fun: (function) optional
           
        Returns:
            (Result)
        """
        found_idx = find_fun(self.key, request)
        result = Result()
        if sum(found_idx) >= 1:
            result.is_successfull = True
            result.key = get_key_by_idx_first(found_idx)
            result.values = get_values_by_idx_first(found_idx)
        return result
   
    def put(key, values):
    """
    Duplicates are acceptable.
    """
        self.key = pd.concat([self.key, key])
        values.name = key.VariableName
        self.values = pd.concat([self.values, values])
        return self
   
    def to_excel(self, excel_out, sheet_name):
        self.key.T.iloc[0:14].to_excel(excel_out, sheet_name=sheet_name, header=False)
        self.values.to_excel(excel_out, sheet_name=sheet_name, startrow=15)

Jestem co prawda dopiero w liceum i nie za bardzo mi do tego żeby znać sztukę, lecz co mi się rzuciło w oczy, to że można by na klasie Request rzucić adnotacją @dataclass. Wiem, że raczej nie o to Ci chodziło, ale chyba fajnie znać. https://docs.python.org/3/library/dataclasses.html

A czy zwracanie self jest na pewno OK?

taki protip zamiast dodawac sobie stringi ->

 def __str__(self):
        return f'{self.variable} {self.code} {self.period} {self.currency}'