ODE of Second order in python

Question

import  sympy  as  sym
sym.init_printing() 
import  scipy  as  sp
import  matplotlib  as  mpl 
import  matplotlib.pyplot  as  plt
#%%
x  =  sym.symbols('x') 
f,  g  =  sym.symbols('f  g',  cls=sym.int)

# f''+ 30000*f'+ 100000000*f = 0.001
# f(0) = 0 e f'(0) = 0
diffeq  =  sym.Eq(f(x).diff(x,  x)  +  (30000)*f(x).diff(x)  +  (100000000)*f(x), sym.(0.001))
 
soln  =  sym.dsolve(diffeq,f(x))

constants = sym.solve([soln.rhs.subs(x,0) - 0, soln.rhs.diff(x,1).subs(x,0)- 0])

C1, C2 = sym.symbols('C1,C2')
soln = soln.subs(constants)

func = sym.lambdify(x,soln.rhs,'numpy')
#%% 
#ploting the solution f(x)
xx  =  sp.arange(-1,1,.01)  
y  =  func(xx)
plt.figure(1) 
plt.plot(xx,y);

Hi! I want to solve this ODE of second order in python but it seems I'm doing something wrong. f'' means the second derivate of f(x) f' means the first derivate of f(x)