Sure, here's the Python code to simulate rolling the five dice and checking for a Yahtzee:
```python
import random
# Function to check if it's a Yahtzee
def is_yahtzee(dice):
return all(die == dice[0] for die in dice)
# Simulating rolling the dice 777 times
for i in range(777):
# Populating the list with five random numbers between 1 & 6
dice = [random.randint(1,6) for _ in range(5)]
# Checking for a Yahtzee and printing the statement if true
if is_yahtzee(dice):
print(f"You rolled {dice} and it's a Yahtzee!")
```
In this code, we first define a function `is_yahtzee` that takes a list of dice values and checks if all the values are the same.
Then, we use a loop to simulate rolling the dice 777 times. For each roll, we create a list `dice` with five random numbers between 1 and 6 using a list comprehension.
Finally, we check if it's a Yahtzee by calling the `is_yahtzee` function with the `dice` list as an argument. If it is a Yahtzee, we print the statement with the dice values.