Update python-spglib.rst
I added an example for clarity.
@@ -169,6 +169,21 @@ as a list of N floating point values.
numbers = [n_1, n_2, n_3, ...]
magmoms = [m_1, m_2, m_3, ...] # Only works with get_symmetry
+
+For example, the crystal structure (``cell``) of L1 `2`:sub: -type AlNi `3`:sub: is:
+
+::
+
+ lattice = [[1.0, 0.0, 0.0],
+ [0.0, 1.0, 0.0],
+ [0.0, 0.0, 1.0]]
+ positions = [[0.0, 0.0, 0.0], # Al
+ [0.5, 0.5, 0.0], # Ni
+ [0.0, 0.5, 0.5], # Ni
+ [0.5, 0.0, 0.5]] # Ni
+ numbers = [1, 2, 2, 2] # Al, Ni, Ni, Ni
+
+
Version 1.9.5 or later: The methods that use the crsytal strcutre
will return ``None`` when a crystal structure is not properly given.
