Output not expected in the file (infinity loop) CSV Python

Well, I'm trying to save the distance and time as a result of the difference in the sending / receiving time of ultrasonic sound, through the sensor for Raspberry Pi 3 HC-SR04!

After getting these values to draw charts with the SeaBorn library, to do this I wanted the data to be written to a CSV file, but this does not happen, the script is in an infinite loop and always replaces the values on the same line in the first according to the file it weighs 15 bytes in the next second it already weighs 0 bytes, anyway I can not get it to write in a new line! I'm new to Python, so I do not know much about looping techniques or which methods to use!

Requirements:

The code is below:

#Libraries
import os
import RPi.GPIO as GPIO
import time
import csv

#GPIO Mode (BOARD / BCM)
GPIO.setmode(GPIO.BCM)

#set GPIO Pins
GPIO_TRIGGER = 23
GPIO_ECHO = 24

#set GPIO direction (IN / OUT)
GPIO.setup(GPIO_TRIGGER, GPIO.OUT)
GPIO.setup(GPIO_ECHO, GPIO.IN) 

#set CSV
currentPath = os.getcwd()
csv_files = currentPath + "/data_sensor.csv"
csv_columns = ['Time', 'Distance']

def WriteDictToCSV(csv_files, csv_columns, dict_data):
    new_file = False
    try:
        if not os.path.exists(csv_files):
            new_file = True

        with open(csv_files, 'a+') as csvfile:
            writer = csv.DictWriter(csvfile, fieldnames=csv_columns)
            if new_file:
                writer.writeheader()
            for data in dict_data:
                writer.writerow(data)
    except IOError as err:
        print("I/O error({})".format(err))    

def distance():
    # set Trigger to HIGH
    GPIO.output(GPIO_TRIGGER, True)

    # set Trigger after 0.01ms to LOW
    time.sleep(0.00001)
    GPIO.output(GPIO_TRIGGER, False)

    StartTime = time.time()
    StopTime = time.time()

    # save StartTime
    while GPIO.input(GPIO_ECHO) == 0:
        StartTime = time.time()

    # save time of arrival
    while GPIO.input(GPIO_ECHO) == 1:
        StopTime = time.time()

    # time difference between start and arrival
    TimeElapsed = StopTime - StartTime
    # multiply with the sonic speed (34300 cm/s)
    # and divide by 2, because there and back
    Distance = (TimeElapsed * 34300) / 2

    return Distance, TimeElapsed

    if __name__ == '__main__':
        try:
            while True:
                d, t = distance()
                dict_data = {t: d}
                WriteDictToCSV(csv_files, csv_columns, dict_data)
                print('Time Elapsed: {} ms | Distance: {} cm'.format(t,d))
                time.sleep(0.5)
        # Reset by pressing CTRL + C
        except KeyboardInterrupt:
            print("Measurement stopped by User")
            GPIO.cleanup()

Note: Script is not yet complete, more data will be exported and formatted!

For those who do not have an Rpi or HC-SR04, here is a minified version of the code:

import os
import csv

currentPath = os.getcwd()
csv_files = currentPath + "/data_sensor.csv"
csv_columns = ['Time', 'Distance']

def WriteDictToCSV(csv_files, csv_columns, dict_data):
    try:
        with open(csv_files, 'a') as csvfile:
            writer = csv.DictWriter(csvfile, fieldnames=csv_columns)
            writer.writeheader()
            for data in dict_data:
                writer.writerow(data)
    except IOError as err:
        print("I/O error({})".format(err))    
    return

if __name__ == '__main__':
    while True:
        # "d" respresenta a distancia de 12 cm e "t" representa o tempo em ms
        d, t = 12, 0.14732832
        dict_data = {t: d}
        WriteDictToCSV(csv_files, csv_columns, dict_data)
        #print('Time Elapsed: {} ms | Distance: {} cm'.format(t,d))

Error output is as follows:

Traceback (most recent call last):
  File "/home/pi/Documents/main1.py", line 70, in <module>
    WriteDictToCSV(csv_files, csv_columns, dict_data)
  File "/home/pi/Documents/main1.py", line 34, in WriteDictToCSV
    writer.writerow(data)
  File "/usr/lib/python3.5/csv.py", line 153, in writerow
    return self.writer.writerow(self._dict_to_list(rowdict))
  File "/usr/lib/python3.5/csv.py", line 146, in _dict_to_list
    wrong_fields = [k for k in rowdict if k not in self.fieldnames]
TypeError: 'float' object is not iterable