code: def passthrough_proc(self, inputstring, **kwargs):
          
          out = []
          found = None  # store of characters that might be the start of a passthrough
          hold = None  # the contents of the passthrough so far
          count = None  # current parenthetical level (num closes - num opens)
          multiline = None  # if in a passthrough, is it a multiline passthrough
          skips = self.copy_skips()
  
          for i, c in enumerate(append_it(inputstring, "\n")):
              if hold is not None:
                  # we specify that we only care about parens, not brackets or braces
                  count += paren_change(c, opens="(", closes=")")
                  if count >= 0 and c == hold:
                      out.append(self.wrap_passthrough(found, multiline))
                      found = None
                      hold = None
                      count = None
                      multiline = None
                  else:
                      if c == "\n":
                          skips = addskip(skips, self.adjust(lineno(i, inputstring)))
                      found += c
              elif found:
                  if c == "\\":
                      found = ""
                      hold = "\n"
                      count = 0
                      multiline = False
                  elif c == "(":
                      found = ""
                      hold = ")"
                      count = -1
                      multiline = True
                  else:
                      out.append("\\" + c)
                      found = None
              elif c == "\\":
                  found = True
              else:
                  out.append(c)
  
          if hold is not None or found is not None:
              raise self.make_err(CoconutSyntaxError, "unclosed passthrough", inputstring, i)
  
          self.set_skips(skips)
          return "".join(out)
docs: Process python passthroughs.