Write a function that describes the cost to have your vehicle towed if you are charged $15 for the pickup plus $2 for every mile.

To describe the cost of towing a vehicle, we can create a function named "tow_cost" that takes the number of miles as input and returns the total cost of towing.

Here is the function in Python:

```python
def tow_cost(miles):
pickup_cost = 15
mileage_cost = 2 * miles
total_cost = pickup_cost + mileage_cost
return total_cost
```

Explanation:
- The function `tow_cost` takes the parameter `miles` representing the number of miles the vehicle is being towed.
- The variable `pickup_cost` stores the fixed cost of $15 for the pickup.
- The variable `mileage_cost` calculates the cost of $2 per mile by multiplying the number of miles by 2.
- The variable `total_cost` calculates the total cost by summing the pickup cost and mileage cost.
- Finally, the function returns the calculated `total_cost`.

You can use this function to calculate the cost of towing a vehicle by providing the number of miles the vehicle will be towed as an input to the function.