def retrieveData(self, username=None, password=None, headers=None, verify=True, cert=None):
url = self.reference<EOL>if url is None:<EOL><INDENT>return "<STR_LIT>"<EOL><DEDENT>log.info('<STR_LIT>' % url)<EOL>if '<STR_LIT:?>' in url:<EOL><INDENT>spliturl = url.split('<STR_LIT:?>')<EOL>u = openURL(spliturl[<NUM_LIT:0>], spliturl[<EOL><NUM_LIT:1>], method='<STR_LIT>', username=username, password=password,<EOL>headers=headers, verify=verify, cert=cert)<EOL>self.fileName = spliturl[<NUM_LIT:1>].split('<STR_LIT:=>')[<NUM_LIT:1>]<EOL><DEDENT>else:<EOL><INDENT>u = openURL(<EOL>url, '<STR_LIT>', method='<STR_LIT>', username=username, password=password,<EOL>headers=headers, verify=verify, cert=cert)<EOL>self.fileName = url.split('<STR_LIT:/>')[-<NUM_LIT:1>]<EOL><DEDENT>return u.read()<EOL>
Method to retrieve data from server-side reference:
returns "" if the reference is not known.

:param username: credentials to access the remote WPS server
:param password: credentials to access the remote WPS server