Basis
=====

Collection of :class:`gauxc.Shell` entries representing a Gaussian basis.

Constructor
-----------

.. code-block:: python

   Basis(shells=[])

Parameters
----------
* **shells** *(list[Shell], optional)* — list of basis shells.

Properties
----------
* ``nao`` — total number of basis functions (AOs).
* ``ncart`` — total number of Cartesian functions.
* ``max_l`` — maximum angular momentum.
* ``norms`` — normalization factors for spherical functions.

List behavior
-------------
* Supports ``len(basis)``, indexing and iteration.

Example
-------

.. code-block:: python

   shells = [s_shell, p_shell, d_shell]
   basis = gxc.Basis(shells)
   print(f"Total AOs: {basis.nao}")
   print(f"Max L: {basis.max_l}")