text: #!/usr/bin/env python
  # -*- coding:utf-8 -*-
  #
  # written by Shotaro Fujimoto
  
  
  class Euler(object):
  
      def __init__(self, function):
          """ Initialize function."""
          self.function = function
  
      def solve(self, y, t, h):
          """ Solve the system ODEs.
  
          --- arguments ---
          y: Array of initial values (ndarray)
          t: Time (float)
          h: Stepsize (float)
          """
          return y + h * self.function(t, y)
  