original_docstring: r"""Write lines allowing extraction of the only element from a single
          element array as a stand-alone variable if the variable is an array
          and only has one element.
  
          Args:
              output_var (str): Name of the variable that should be conditionally
                  expanded.
              add_cond (str, optional): Additional condition that must be
                  satisfied for the array element to be extracted. Defaults to
                  False and is ignored.
  
          Returns:
              list: Lines added the conditional expansion of single element
                  arrays.
  
          
docstring: r"""Write lines allowing extraction of the only element from a single
  element array as a stand-alone variable if the variable is an array
  and only has one element.
docstring_tokens: r " " " Write lines allowing extraction of the only element from a single element array as a stand - alone variable if the variable is an array and only has one element .
code: def write_expand_single_element(cls, output_var, add_cond=False):
          r"""Write lines allowing extraction of the only element from a single
          element array as a stand-alone variable if the variable is an array
          and only has one element.
  
          Args:
              output_var (str): Name of the variable that should be conditionally
                  expanded.
              add_cond (str, optional): Additional condition that must be
                  satisfied for the array element to be extracted. Defaults to
                  False and is ignored.
  
          Returns:
              list: Lines added the conditional expansion of single element
                  arrays.
  
          """
          if not add_cond:
              add_cond = []
          add_cond.append(f"is.null(names({output_var}))")
          return super(RModelDriver, cls).write_expand_single_element(
              output_var, add_cond)
code_tokens: def write_expand_single_element ( cls , output_var , add_cond = False ) : if not add_cond : add_cond = [ ] add_cond . append ( f"is.null(names({output_var}))" ) return super ( RModelDriver , cls ) . write_expand_single_element ( output_var , add_cond )
short_docstring: r"""Write lines allowing extraction of the only element from a single
  element array as a stand-alone variable if the variable is an array
  and only has one element.
short_docstring_tokens: r " " " Write lines allowing extraction of the only element from a single element array as a stand - alone variable if the variable is an array and only has one element .
comment: r"""Write lines allowing extraction of the only element from a single
          element array as a stand-alone variable if the variable is an array
          and only has one element.
  
          Args:
              output_var (str): Name of the variable that should be conditionally
                  expanded.
              add_cond (str, optional): Additional condition that must be
                  satisfied for the array element to be extracted. Defaults to
                  False and is ignored.
  
          Returns:
              list: Lines added the conditional expansion of single element
                  arrays.
  
          """