code: def add_var_declaration(self, size):
      return self.get_var_name()
  
file_path: m2cgen/m2cgen/interpreters/r/code_generator.py
imports: from contextlib import contextmanager
  from m2cgen.interpreters.code_generator import CLikeCodeGenerator, CodeTemplate
label_desc: Use image node_id 1 for calling the RCodeGenerator obj's underlying member method code with example usage: obj.add_var_declaration(size) and returns: self