Move import statements inside function body

Author: rusydi

src/sage/crypto/sboxes.py

@@ -166,9 +166,6 @@
 """
 import sys
 
-from sage.rings.integer_ring import ZZ
-from sage.rings.finite_rings.finite_field_constructor import GF
-from sage.modules.free_module_element import vector
 from sage.crypto.sbox import SBox
 from sage.misc.functional import is_odd, is_even
 
@@ -424,6 +421,10 @@ def chi(n):
         (0, 9, 18, 11, 5, 12, 22, 15, 10, 3, 24, 1, 13, 4, 30, 7, 20, 21, 6,
         23, 17, 16, 2, 19, 26, 27, 8, 25, 29, 28, 14, 31)
     """
+    from sage.rings.integer_ring import ZZ
+    from sage.rings.finite_rings.finite_field_constructor import GF
+    from sage.modules.free_module_element import vector
+    
     table = [0]*(1 << n)
 
     for x in range(1 << n):