text: import numpy as np 
  import matplotlib.pyplot as plt
  from datetime import datetime
  
  def nowstring():
  	"""Generate a unite datetime for saving data
  	"""
  	return datetime.now().strftime("%Y-%m-%d_%H-%M-%S") 
  
  
  def save_fig(loc):
  	plt.savefig(str(loc)+'.pdf',dpi=300, bbox_inches = 'tight',
      pad_inches = 0)
  	plt.savefig(str(loc)+'.png',dpi=300, bbox_inches = 'tight',
  	    pad_inches = 0)
  	plt.savefig(str(loc)+'.svg',dpi=300, bbox_inches = 'tight',
  	    pad_inches = 0)
  	plt.savefig(str(loc)+'.png',dpi=300, bbox_inches = 'tight',
  	    pad_inches = 0)
  	plt.savefig(str(loc)+'.jpg',dpi=150, bbox_inches = 'tight',
  	    pad_inches = 0)