B �.`��@spdZddlmZmZmZddlmZddlmZm Z m Z esLddlZddlZddd gZ d d�Zedfdd �ZdS)z Commonly useful converters. �)�absolute_import�division�print_function�)�PY2)�NOTHING�Factory�pipeNr �optional�default_if_nonec s��fdd�}ts�d}yt��}Wnttfk r:YnX|r�t|j��}|rz|djtj j k rztj|dj|j d<|jtjj k r�tj|j|j d<|S)aO A converter that allows an attribute to be optional. An optional attribute is one which can be set to ``None``. Type annotations will be inferred from the wrapped converter's, if it has any. :param callable converter: the converter that is used for non-``None`` values. .. versionadded:: 17.1.0 cs|dkrdS�|�S)N�)�val)� converterr�@/opt/alt/python37/lib/python3.7/site-packages/attr/converters.py�optional_converter%sz$optional..optional_converterNrr �return)r�inspect� signature� ValueError� TypeError�list� parameters�values� annotation� Parameter�empty�typing�Optional�__annotations__�return_annotation� Signature)rr�sig�paramsr)rrr s csv�tkr|dkrtd��tk r0|dk r0td��|dk r@t|��t�t�rf�jrXtd��fdd�}n�fdd�}|S)a� A converter that allows to replace ``None`` values by *default* or the result of *factory*. :param default: Value to be used if ``None`` is passed. Passing an instance of `attr.Factory` is supported, however the ``takes_self`` option is *not*. :param callable factory: A callable that takes no parameters whose result is used if ``None`` is passed. :raises TypeError: If **neither** *default* or *factory* is passed. :raises TypeError: If **both** *default* and *factory* are passed. :raises ValueError: If an instance of `attr.Factory` is passed with ``takes_self=True``. .. versionadded:: 18.2.0 Nz(Must pass either `default` or `factory`.z5Must pass either `default` or `factory` but not both.z1`takes_self` is not supported by default_if_none.cs|dk r|S��S)N)�factory)r )�defaultrr�default_if_none_converterasz2default_if_none..default_if_none_convertercs|dk r|S�S)Nr)r )r$rrr%is)rrr� isinstanceZ takes_selfr)r$r#r%r)r$rr>s )�__doc__� __future__rrr�_compatr�_makerrr rr�__all__r rrrrr�s'