class_docstr: See module docs.
docstr: Potentially cheaper than getvalue as no string concatenation
  needs to happen.
code: def copyto(self, target):
      """Potentially cheaper than getvalue as no string concatenation
      needs to happen."""
      for child in self.prepended_children:
          child.copyto(target)
      stream_content = self.stream.getvalue()
      if stream_content:
          target.write(stream_content)
  
file_path: catboost/contrib/tools/cython/Cython/StringIOTree.py
imports: from __future__ import absolute_import
label_desc: Use image node_id 3 for calling the StringIOTree obj's underlying member method code with example usage: obj.copyto(target) without return types