Method from_instance_helper

src/err.rs:268–294

(py: Python, obj: PyObject)

    }

    fn from_instance_helper(py: Python, obj: PyObject) -> PyErr {
        if unsafe { ffi::PyExceptionInstance_Check(obj.as_ptr()) } != 0 {
            PyErr {
                ptype: unsafe {
                    PyObject::from_borrowed_ptr(py, ffi::PyExceptionInstance_Class(obj.as_ptr()))
                },
                pvalue: Some(obj),
                ptraceback: None,
            }
        } else if unsafe { ffi::PyExceptionClass_Check(obj.as_ptr()) } != 0 {
            PyErr {
                ptype: obj,
                pvalue: None,
                ptraceback: None,
            }
        } else {
            PyErr {
                ptype: py.get_type::<exc::TypeError>().into_object(),
                pvalue: Some(
                    "exceptions must derive from BaseException"
                        .to_py_object(py)
                        .into_object(),
                ),
                ptraceback: None,
            }
        }
    }

    /// Construct a new error, with the usual lazy initialization of Python exceptions.
    /// `exc` is the exception type; usually one of the standard exceptions like `py.get_type::<exc::RuntimeError>()`.