input: Write a python function to find the first non-negative value in a list.
  assert find_value([-5, 0, 4, -1, 3]) == 0
  assert find_value([-10, -20, -30]) == -1
  assert find_value([3, -2, 5, -1, 0]) == 3
output: def find_value(lst):
      for num in lst:
          if num >= 0:
              return num
      return -1