Pickle Example

gistfile1.py

from sympy import Symbol, lambdify
import pickle

def main():
  input_symbols = [Symbol('a'), Symbol('b')]
  my_equation = Symbol('x') = Symbol('a') + Symbol('b')
  
  save(input_symbols, my_equation, 'random_file')

def save(input_symbols, equation, filename):
  output_symbols = [str(sym) for sym in input_symbols]
  output_equation = str(my_equation)

  output = {'equation': output_equation, 'input_symbols': output_symbols}

  with open(filename, 'w') as f:
    pickle.dump(output, f)
    
def load(filename):
  with open(filename, 'r') as f:
    output_symbols = output['input_symbols']
    output_equation = output['equation']
  
    equation = Symbol(output_equation)
    input_symbols = [Symbol(sym) for sym in output_symbols]
    
    return lambdify(input_symbols, equation)