re-add readline method to stream class because doc formatting removed…

… it somehow

interpreter/code_interpreters/container_utils.py

@@ -154,6 +154,19 @@ def __init__(self, parent, read_fd):
             self.parent = parent
             self._read_fd = read_fd
             self._buffer = ""
+
+        def readline(self, timeout=3):
+            while '\n' not in self._buffer:
+                ready_to_read, _, _ = select.select([self._read_fd], [], [], timeout)
+                if not ready_to_read:
+                    return ''
+                chunk = os.read(self._read_fd, 1024).decode('utf-8')
+                self._buffer += chunk
+
+            newline_pos = self._buffer.find('\n')
+            line = self._buffer[:newline_pos]
+            self._buffer = self._buffer[newline_pos + 1:]
+            return line
 
     def _listen(self):
         while not self._stop_event.is_set():