code: def find_requirements(max_depth=3):
      
      i = 0
      for c, d, f in walk_up(os.getcwd()):
          i += 1
          if i < max_depth:
              if "requirements.txt":
                  r = os.path.join(c, "requirements.txt")
                  if os.path.isfile(r):
                      return r
  
      raise RuntimeError("No requirements.txt found!")
docs: Returns the path of a Pipfile in parent directories.