code: def add_var_declaration(self, size):
      var_name = self.get_var_name()
  
      if size > 1:
          tpl = self.tpl_vector_var_declare
      else:
          tpl = self.tpl_scalar_var_declare
  
      self.add_code_line(tpl(var_name=var_name, size=size))
      return var_name
  
file_path: m2cgen/m2cgen/interpreters/c/code_generator.py
imports: from contextlib import contextmanager
  from m2cgen.interpreters.code_generator import CLikeCodeGenerator, CodeTemplate
label_desc: Use image node_id 3 for calling the CCodeGenerator obj's underlying member method code with example usage: obj.add_var_declaration(size) and returns: var_name