'SymPy provides two different internal kinds of representation
of associative words. The first one is called the `array_form`
which is a tuple containing `tuples` as its elements, where the
size of each tuple is two. At the first position the tuple
contains the `symbol-generator`, while at the second position
of tuple contains the exponent of that generator at the position.
Since elements (i.e. words) don\'t commute, the indexing of tuple
makes that property to stay.
The structure in ``array_form`` of ``FreeGroupElement`` is of form:
``( ( symbol_of_gen , exponent ), ( , ), ... ( , ) )``
Examples
>>> from sympy.combinatorics.free_groups import free_group
>>> f, x, y, z = free_group("x y z")
>>> (x*z).array_form
((x, 1), (z, 1))
>>> (x**2*z*y*x**2).array_form
((x, 2), (z, 1), (y, 1), (x, 2))
See Also
letter_repr'

@property
def array_form(self):

    return tuple(self)
