def _interp(arr, v, _Series=pd.Series, _charmod=np.char.mod):
 if (len(arr) >= 145):
  return (_Series(arr) % v)
 return _charmod(arr, v)

def _interp ( arr , v , _Series = pd . Series , _charmod = np . char . mod ) : if ( len ( arr ) >= 145 ) : return ( _Series ( arr ) % v ) return _charmod ( arr , v )
delegate to the most efficient string formatting technique based on the length of the array .