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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:

def get_meta(self, name, meta_key=None):
        '''Get the ``content`` attribute of a meta tag ``name``.

        For example::

            head.get_meta('decription')

        returns the ``content`` attribute of the meta tag with attribute
        ``name`` equal to ``description`` or ``None``.
        If a different meta key needs to be matched, it can be specified via
        the ``meta_key`` parameter::

            head.get_meta('og:title', meta_key='property')
        '''
        meta_key = meta_key or 'name'
        for child in self.meta._children:
            if isinstance(child, Html) and child.attr(meta_key) == name:
                return child.attr('content')