Find the domain of the function.
\[
f(x)=\ln (7-2 x)
\]

Write your answer as an interval or union of intervals.

Step 1 ：The domain of a function is the set of all possible input values (x-values) which will produce a valid output.

Step 2 ：For the function \(f(x) = \ln(7-2x)\), the argument of the logarithm (7-2x) must be greater than zero, because the logarithm of a non-positive number is undefined.

Step 3 ：Therefore, we need to solve the inequality 7-2x > 0 to find the domain of the function.

Step 4 ：The solution to the inequality 7-2x > 0 is x < 7/2.

Step 5 ：This means that the domain of the function \(f(x) = \ln(7-2x)\) is all real numbers less than 7/2.

Step 6 ：Final Answer: The domain of the function is \(\boxed{(-\infty, \frac{7}{2})}\).