def add_sample_tag_value(self, tag_name, new_sample_values):
if tag_name in self.format_tags:<EOL><INDENT>msg = "<STR_LIT>".format(tag_name)<EOL>raise KeyError(msg)<EOL><DEDENT>if not self._samples_match(new_sample_values):<EOL><INDENT>raise KeyError("<STR_LIT>"<EOL>"<STR_LIT>")<EOL><DEDENT>for sample in self.sample_tag_values.keys():<EOL><INDENT>value = str(new_sample_values[sample])<EOL>self.sample_tag_values[sample][tag_name] = value<EOL><DEDENT>
Appends a new format tag-value for all samples.

        Args:
            tag_name: string tag name; must not already exist
            new_sample

        Raises:
            KeyError: if tag_name to be added already exists