Add a ``field:value`` term to the query.
        Matches will have the ``value`` in the ``field``.

        Arguments:
            field (str): The field to check for the value.
                    The field must be namespaced according to Elasticsearch rules
                    using the dot syntax.
                    For example, ``"mdf.source_name"`` is the ``source_name`` field
                    of the ``mdf`` dictionary.
            value (str): The value to match.
            required (bool): If ``True``, will add term with ``AND``.
                    If ``False``, will use ``OR``. **Default:** ``True``.
            new_group (bool): If ``True``, will separate the term into a new parenthetical group.
                    If ``False``, will not.
                    **Default:** ``False``.

        Returns:
            SearchHelper: Self

def match_field(self, field, value, required=True, new_group=False):
        """Add a ``field:value`` term to the query.
        Matches will have the ``value`` in the ``field``.

        Arguments:
            field (str): The field to check for the value.
                    The field must be namespaced according to Elasticsearch rules
                    using the dot syntax.
                    For example, ``"mdf.source_name"`` is the ``source_name`` field
                    of the ``mdf`` dictionary.
            value (str): The value to match.
            required (bool): If ``True``, will add term with ``AND``.
                    If ``False``, will use ``OR``. **Default:** ``True``.
            new_group (bool): If ``True``, will separate the term into a new parenthetical group.
                    If ``False``, will not.
                    **Default:** ``False``.

        Returns:
            SearchHelper: Self
        """
        # If not the start of the query string, add an AND or OR
        if self.initialized:
            if required:
                self._and_join(new_group)
            else:
                self._or_join(new_group)
        self._field(field, value)
        return self