'Returns a dense, mutable matrix with elements represented explicitly
Examples
>>> from sympy import Identity
>>> I = Identity(3)
>>> I
I
>>> I.shape
(3, 3)
>>> I.as_mutable()
Matrix([
[1, 0, 0],
[0, 1, 0],
[0, 0, 1]])
See Also
as_explicit: returns ImmutableDenseMatrix'

def as_mutable(self):

    return self.as_explicit().as_mutable()
