def get_normalized_parameters(self):
        """Return a string that contains the parameters that must be signed."""
        params = self.parameters
        try:
            # Exclude the signature if it exists.
            del params['oauth_signature']
        except:
            pass
        # Escape key values before sorting.
        key_values = [(escape(_utf8_str(k)), escape(_utf8_str(v))) \
            for k,v in params.items()]
        # Sort lexicographically, first after key, then after value.
        key_values.sort()
        # Combine key value pairs into a string.
        return '&'.join(['%s=%s' % (k, v) for k, v in key_values])
Return a string that contains the parameters that must be signed.
twitter/oauth.py