old_contents: import StringIO
  import base64
  import signal
  
  from flask import Flask, render_template, request, make_response
  
  from quiver.plotter import FieldPlotter
  
  app = Flask(__name__)
  
  @app.route('/')
  def quiver():
      '''Route for homepage'''
      return render_template('quiver.html')
  
  @app.route('/plot/', methods=['GET',])
  def plot():
      equation_string = request.args.get('equation')
      diff_equation = FieldPlotter()
      diff_equation.set_equation_from_string(equation_string)
      diff_equation.make_plot()
      
      # If plotting was successful, write plot out
      if diff_equation.figure:
          
          # Write output to memory and add to response object
          output = StringIO.StringIO()
          response = make_response(base64.b64encode(diff_equation.write_data(output)))
          response.mimetype = 'image/png'
          return response
      else:
          return make_response('')
  
  @app.route('/data/', methods=['GET',])
  def data():
      equation_string = request.args.get('equation')
      plotter = FieldPlotter()
      plotter.set_equation_from_string(equation_string)
      plotter.make_data()
  
  if __name__ == '__main__':
      app.run(debug=True)
new_contents: import StringIO
  import base64
  import signal
  
  import flask
  
  from quiver.plotter import FieldPlotter
  
  app = flask.Flask(__name__)
  
  @app.route('/')
  def quiver():
      '''Route for homepage'''
      return flask.render_template('quiver.html')
  
  @app.route('/plot/', methods=['GET',])
  def plot():
      equation_string = flask.request.args.get('equation')
      diff_equation = FieldPlotter()
      diff_equation.set_equation_from_string(equation_string)
      diff_equation.make_plot()
      
      # If plotting was successful, write plot out
      if diff_equation.figure:
          
          # Write output to memory and add to response object
          output = StringIO.StringIO()
          response = flask.make_response(base64.b64encode(diff_equation.write_data(output)))
          response.mimetype = 'image/png'
          return response
      else:
          return flask.make_response('')
  
  @app.route('/data/', methods=['GET',])
  def data():
      equation_string = flask.request.args.get('equation')
      plotter = FieldPlotter()
      plotter.set_equation_from_string(equation_string)
      plotter.make_data()
  
  if __name__ == '__main__':
      app.run(debug=True)
subject: Change import level of flask.