code: def footprint(self, nside=None):
          
          if nside is None:
              nside = self.nside_pixel
          elif nside < self.nside_catalog: 
              raise Exception('Requested nside=%i is less than catalog_nside'%nside)
          elif nside > self.nside_pixel:
              raise Exception('Requested nside=%i is greater than pixel_nside'%nside)
          pix = np.arange(hp.nside2npix(nside), dtype=int)
          map = self.inFootprint(pix,nside)
          return map
docs: UNTESTED.
          Should return a boolean array representing the pixels in the footprint.