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

        Note:
            This method triggers advanced mode.

        Arguments:
            field (str): The field to check for the value, in Elasticsearch dot syntax.
            value (str): The value to match.

        Returns:
            SearchHelper: Self

def _field(self, field, value):
        """Add a ``field:value`` term to the query.
        Matches will have the ``value`` in the ``field``.

        Note:
            This method triggers advanced mode.

        Arguments:
            field (str): The field to check for the value, in Elasticsearch dot syntax.
            value (str): The value to match.

        Returns:
            SearchHelper: Self
        """
        # Fields and values must be strings for Elasticsearch
        field = str(field)
        value = str(value)

        # Check if quotes required and allowed, and quotes not present
        # If the user adds improper double-quotes, this will not fix them
        if (any([char in value for char in QUOTE_LIST]) and '"' not in value
                and not any([char in value for char in UNQUOTE_LIST])):
            value = '"' + value + '"'

        # Cannot add field:value if one is blank
        if field and value:
            self.__query["q"] += field + ":" + value
            # Field matches are advanced queries
            self.__query["advanced"] = True

        return self