*Lookup the ID of HTM trixel that a coordinate or lists of coordinates lie on*

        **Key Arguments:**
            - ``ra`` -- list, numpy array or single ra value (first coordinate set)
            - ``dec`` -- list, numpy array or single dec value (first coordinate set - must match ra1 array length)

        **Return:**
            - ``htmIds`` -- a list of HTM trixel ids the coordinates lie on

        **Usage:**

            To find the trixel IDs that a set of coordinate lie on:

            .. code-block:: python

                raList1 = ["13:20:00.00", 200.0, "13:20:00.00", 175.23, 21.36]
                decList1 = ["+24:18:00.00",  24.3,  "+24:18:00.00",  -28.25, -15.32]

                htmids = mesh.lookup_id(raList1, decList1)
                for h, r, d in zip(htmids, raList1, decList1):
                    print r, d, " --> ", h

def lookup_id(
            self,
            ra,
            dec):
        """*Lookup the ID of HTM trixel that a coordinate or lists of coordinates lie on*

        **Key Arguments:**
            - ``ra`` -- list, numpy array or single ra value (first coordinate set)
            - ``dec`` -- list, numpy array or single dec value (first coordinate set - must match ra1 array length)

        **Return:**
            - ``htmIds`` -- a list of HTM trixel ids the coordinates lie on

        **Usage:**

            To find the trixel IDs that a set of coordinate lie on:

            .. code-block:: python

                raList1 = ["13:20:00.00", 200.0, "13:20:00.00", 175.23, 21.36]
                decList1 = ["+24:18:00.00",  24.3,  "+24:18:00.00",  -28.25, -15.32]

                htmids = mesh.lookup_id(raList1, decList1)
                for h, r, d in zip(htmids, raList1, decList1):
                    print r, d, " --> ", h

        """
        self.log.debug('starting the ``lookup_id`` method')

        from astrocalc.coords import coordinates_to_array
        raArray, decArray = coordinates_to_array(
            log=self.log,
            ra=ra,
            dec=dec
        )

        self.log.debug('completed the ``lookup_id`` method')
        return super(HTM, self).lookup_id(raArray, decArray)