return blob content from StorageBlobModel instance to a string. Parameters are:

def totext(self) ->str:
        """ 
        return blob content from StorageBlobModel instance to a string. Parameters are:
        """
        sreturn = ''
        if self.properties.content_settings.content_encoding is None:
            raise AzureStorageWrapException(self, 'can not convert blob {!s} to text because content_encoding is not given'.format(self.name))
        else:
            sreturn = self.content.decode(self.properties.content_settings.content_encoding, 'ignore')

        return sreturn