new_contents: import numpy as np
  
  from constants import ODE_SYSTEMS, PARAMS_ID
  from data_io import read_params, write_params
  
  
  class Params(object):
  
      def __init__(self, params, system, init_cond=None):
          alpha_plus, alpha_minus, mu, a, b, c, N, v_x, v_y, v_z, mu_base = params
          # vector of params
          self.params = params
          # params as scalars
          self.alpha_plus = alpha_plus
          self.alpha_minus = alpha_minus
          self.mu = mu
          self.a = a
          self.b = b
          self.c = c
          self.N = N
          self.v_x = v_X
          self.v_y = v_y
          self.v_z = v_z
          self.mu_base = mu_base
          # init_cond as x, y, z
          self.init_cond = init_cond
          # system as defined in constants.pu (e.g. 'default', 'feedback_z')
          assert system in ODE_SYSTEMS
          self.system = system
  
      def __str__(self):
          return self.params
  
      def printer(self):
          for idx in xrange(len(PARAMS_ID.keys())):
              print "Param %d: (%s) = %.3f" % (idx, PARAMS_ID[idx], self.params[idx])
  
      def params_copy(self):  # TODO maybe make this and other copy instead of pass pointer np.zeros(self.N).. etc
          params_copy = self.params[:]
          return params_copy
  
      def write(self, filedir, filename):
          filepath = write_params(self.params, self.system, filedir, filename)
          return filepath
  
      def read(filedir, filedir, filename):
          params_with_system = read_params(filedir, filename)
          params = params_with_system[:-1]
          system = params_with_system[-1]
          assert system in ODE_SYSTEMS
          return Params(params, system, init_cond=None)
  
subject: store model params in Params class