Python compare data from sqlite database is between two date

#import module
import sqlite3

#database path is here
database = 'test.db'

#Testing in the data
#25.09.2017 27.09.2017
#01.10.2017 03.10.2017

class db_conn:
    ''' Class connect main '''
    def __init__(self, db, Fdata=None, Sdata=None):
        self.db = db
        self.Fdata = Fdata
        self.Sdata = Sdata
        self.con = sqlite3.connect(self.db)

    def insert(self):
        ''' insert into database two value's '''
        self.con.execute("INSERT INTO praznik (Fdata, Sdata) VALUES (?, ?)", (self.Fdata, self.Sdata))
        self.con.commit()
        self.con.close()


    def show_table(self):
        ''' Use for select from database '''
        self.cur = self.con.cursor()
        self.cur.execute("SELECT * from praznik")
        for row in self.cur:
            print("First Data {fdata} - Second Data {sdata}".format(fdata=row[1], sdata=row[2]))
        self.con.close()


    def check_period(self, fdata_check, ldata_check):
        ''' check period is valid or not '''
        self.fdata_check = fdata_check
        self.ldata_check = ldata_check
        self.cur = self.con.cursor()
        self.cur.execute("SELECT * from praznik")
        for row in self.cur:
            if row[1] <= self.ldata_check and row[2] >= self.fdata_check:
                print("Problem")
                break
            else:
                print("Look Good")
                break
        self.con.close()

Python use picke to write json to faile and read back to dictionary

#import module
from pprint import pprint  # pretiprint
import json
import os
import pickle
# hard code param
test_file = 'test_file.json'
db = {}
dl = {}

def check_file_exists(filename):
    ''' Check file exists or not '''
    if not os.path.exists(filename):
        open(filename, 'w').close()

def write_in_json(filename, db):
    ''' Write dictionary to file with ekstension json'''
    db = json.dumps(db)
    with open(filename, 'wb') as f:
        pickle.dump(db, f)

def load_from_json_file(filename, dl):
    ''' Load serial object into file to dictionary '''
    json_file = open(filename, 'rb')
    dl = pickle.load(json_file)
    dlj = json.loads(dl)
    return dlj

# Get from enywere for test
borko = {'name': 'Borko', 'ip': '192.168.168.1', 'df': 30000, 'free': 'dev'}
sue = {'name': 'Sue Somebody', 'ip': '192.168.168.2', 'df': 40000, 'free': 'hdw'}
tom = {'name': 'Tom Aks', 'ip': '192.168.168.3', 'df': 0, 'free': None}

db['bob'] = borko
db['sue'] = sue
db['tom'] = tom
if __name__ == '__main__':
    # Create file if not exists uncoment to begin
    # check_file_exists(test_file)
    # function write json to file uncoment to begin
    #write_in_json(test_file, db)
    # fuction load picke file to json object return to dictionary
    #print(load_from_json_file(test_file, dl))