'Perform element-wise absolute value of Tensor `a`, storing the result
in Tensor out. Both Tensor\'s should have identical shape. Implemented as
an alias of absolute.
Arguments:
a (Tensor): input to be transformed.
out (Tensor, optional): where the result will be stored. If out is
None, only the op-tree will be returned.
Returns:
OpTreeNode: the resulting op-tree'

def fabs(self, a, out=None):

    return OpTreeNode.build('abs', a, None, out=out)
