def domain_of_validity(self):
<EOL>domain = self.element.find(GML_NS + '<STR_LIT>')<EOL>domain_href = domain.attrib[XLINK_NS + '<STR_LIT>']<EOL>url = '<STR_LIT>'.format(prefix=EPSG_IO_URL,<EOL>code=domain_href)<EOL>xml = requests.get(url).content<EOL>gml = ET.fromstring(xml)<EOL>def extract_bound(tag):<EOL><INDENT>ns = '<STR_LIT>'<EOL>xpath = '<STR_LIT>'.format(<EOL>ns=ns,<EOL>tag=tag)<EOL>bound = gml.find(xpath)<EOL>return float(bound.text)<EOL><DEDENT>tags = ('<STR_LIT>', '<STR_LIT>',<EOL>'<STR_LIT>', '<STR_LIT>')<EOL>bounds = [extract_bound(tag) for tag in tags]<EOL>return bounds<EOL>
Return the domain of validity for this CRS as:
(west, east, south, north).

For example::

    >>> print(get(21781).domain_of_validity())
    [5.96, 10.49, 45.82, 47.81]