Errore di indentazione

Buongiorno non riesco a capire l'errore che mi restituisce sul seguente codice:

File "C:\Users\loris\Desktop\MY_WRK_SPACE\RBTEST\eul_rot_zyx.py", line 27
   if abs(R.item(0,0)) < tol and abs(R.item(1,0)) < tol:
IndentationError: unexpected indent

linea rossa sotto l'istruzione IF. Come posso risolvere . Non riesco. Grazie 

import numpy as np
import math as m
import sys

def Rx(theta):
  return np.matrix([[1, 0, 0],
                    [0, m.cos(theta), -m.sin(theta)],
                    [0, m.sin(theta),  m.cos(theta)]])
                       
def Ry(theta):
  return np.matrix([[m.cos(theta), 0,  m.sin(theta)],
                    [0, 1, 0],
                    [-m.sin(theta), 0, m.cos(theta)]])
    
def Rz(theta):
  return np.matrix([[m.cos(theta), -m.sin(theta), 0],
                    [m.sin(theta),  m.cos(theta), 0],
                    [0, 0, 1]])
    
phi = m.pi/2
theta = m.pi/4
psi = m.pi/2
eul1=0
R = Rz(psi) * Ry(theta) * Rx(phi)
tol = sys.float_info.epsilon * 10

      if abs(R.item(0,0)) < tol and abs(R.item(1,0)) < tol: //LINEA 27 ERRATA
               eul1 = 0
               eul2 = m.atan2(-R.item(2, 0), R.item(0, 0))
               eul3 = m.atan2(-R.item(1, 2), R.item(1, 1))
          else:
               eul1 = m.atan2(R.item(1, 0),  R.item(0, 0))
               sp = m.sin(eul1)
               cp = m.cos(eul1)
               eul2 = m.atan2(-R.item(2, 0), cp*R.item(0, 0)+sp*R.item(1, 0))
               eul3 = m.atan2(sp*R.item(0, 2)-cp*R.item(1, 2), cp*R.item(1, 1)-sp*R.item(0, 1))
  
print("phi =",  eul1)
print("theta =", eul2)
print("psi =", eul3)