Finding the difference between two dates in months

Is it correct to find the difference between the two datetime

by month, as I found that months_to_maturity

my dataframe column df

stays the same before and after I find the difference. The code I am using is below:

todays_date = datetime.date.today()
#Converting to datetime
datenow = datetime.datetime.combine(todays_date, datetime.datetime.min.time()) 

# Function to find the difference in months between the two datetime objects
def monthdelta(d1, d2):
    delta = 0
    while True:
        mdays = monthrange(d1.year, d1.month)[1]
        d1 += timedelta(days=mdays)
        if d1 <= d2:
            delta += 1
            else:
                break
    return delta 

# Re-assiging months_to_maturity in df with the difference between the two datetimes
for (i,row) in df.iterrows():
    row['months_to_maturity'] = monthdelta(datenow, datetime.datetime.strptime(row['maturity_dt'], '%Y-%m-%d %H:%M:%S.%f'))

      

        
        
        
      

    

thank