r
        There are many instances where such an error can be raised:

        - `target=None`, but the expression is multiline.
        - The expression is multiline, but not all them have item assignment.
          An example of such an arrangement is this:

          a = b + 1
          a + 2

          Here, there are expressions on different lines, making it multiline,
          but the last line has no variable assigned to the output of `a + 2`.
        - `inplace=True`, but the expression is missing item assignment.
        - Item assignment is provided, but the `target` does not support
          string item assignment.
        - Item assignment is provided and `inplace=False`, but the `target`
          does not support the `.copy()` method

    See Also
    --------
    DataFrame.query : Evaluates a boolean expression to query the columns
            of a frame.
    DataFrame.eval : Evaluate a string describing operations on
            DataFrame columns.

    Notes
    -----
    The ``dtype`` of any objects involved in an arithmetic ``%`` operation are
    recursively cast to ``float64``.

    See the :ref:`enhancing performance <enhancingperf.eval>` documentation for
    more details.

    Examples
    --------
    >>> df = pd.DataFrame({"animal": ["dog", "pig"], "age": [10, 20]})
    >>> df
      animal  age
    0    dog   10
    1    pig   20

    We can add a new column using ``pd.eval``:

    >>> pd.eval("double_age = df.age * 2", target=df)
      animal  age  double_age
    0    dog   10          20
    1    pig   20          40
    r<