def time_shift_cond(condition, delta):
    """ Returns the shifted condition file
    
    Parameters:
    -----------
    condition: a 1d np.array of stimulus times
    
    delta: a single numeric value indicating how much to shift.
    
    Returns:
    --------
    shift_condition: 1d np.array time shifted conditional data
    """
    
    shift_condition= condition-delta
    
    return shift_condition