Why does it take double args when calling my class for my class to work? : I am running Python 3.3.4 on Windows 10

The following is my class Code-  


    class Curl():
    
    def __init__(self):
        self.file7 = file7
        self.Days1 = Days1
        
    def readfile(self):
        ticknum = 0
        read_ticker = []
        ins = open(file7, "r" )
        for line in ins:
            if line.endswith('\n'):
                line=line[:-1]
            read_ticker.append(line)
            ticknum =+1
        ins.close()
        return read_ticker
   
    def CalcDates(self, Days1):  # Determine dates
        calculated_dates = dict()
        Run_Time = (time.strftime("%H/%M/%S"))
        calculated_dates['Run_Time']= Run_Time
        Today = date.today()
        calculated_dates['Today'] = Today
        End_Date = (Today - timedelta(days=Days1)) 
        calculated_dates ['Start_Date'] = Today
        Start_Day = str(Today.strftime("%d")) 
        calculated_dates['Start_Day'] = Start_Day
        Start_Month = str(Today.strftime("%m")) 
        calculated_dates['Start_Month'] = Start_Month
        Start_Year = str(Today.strftime("%Y")) 
        calculated_dates['Start_Year']= Start_Year
        End_Day = str(End_Date.strftime("%d"))
        calculated_dates['End_Day'] = End_Day
        End_Month = str(End_Date.strftime("%m"))
        calculated_dates['End_Month']= End_Month
        End_Year = str(End_Date.strftime("%Y"))
        calculated_dates['End_Year']= End_Year
        return calculated_dates


                     
It runs if i do the following;

     file7 = 'C:\\...\\file1.txt'
     fileList = Curl.readfile(file7)
     print('readTickers is complete')
     print(fileList)
     D1= Curl.CalcDates( 90, 90)
     print(D1)

I want it to run if i change the line D1 as follows;
   D1= Curl.CalcDates(90)

but it doesn't- I get the following error;

     Traceback (most recent call last):
     File "C:\Users\Edge\Desktop\readTICKR class432.py", line 56, in <module>
     D1= Curl.CalcDates(90)
     TypeError: CalcDates() missing 1 required positional argument: 'Days1'



Why does it require me to put double arguements when I call Curl.CalcDates ?  
How can I fix it so that I can use a single arguement?