def findValue(tags, tag_name, label_name=None, label_type=None):
        """
        This is a small helper that is used to pull out values from a tag
        given the value of the tags class or id attribute. See the example.

        Parameters:
        -----------
        tag_name : str
            Tag name or type, such as 'li','span', or 'div'
        label_name : str
            Used for selecting a specific value
        label_type: str
            Used to differentiate between 'class' or 'id' labels
        tags : bs4.element.Tag

        Example:
        --------
        # Our goal is to extract: Can. J. Physiol. Pharmacol.
        # One of the tags is:
        <span class="r_publication">Can. J. Physiol. Pharmacol.</span>

        findValue('span', 'class', 'r_publication')

        """
        if label_name is None or label_type is None:
            temp = tags.find(tag_name)
        else:
            temp = tags.find(tag_name, {'%s' % label_type: label_name})

        if temp is None:
            return None
        else:
            text = temp.text.replace('\\xa0', ' ')
            return text