Reduces the atom to an affine expression and list of constraints.

graph_implementation(object, arg_objs, dim, data)

## Arguments

object

An Expression object.

arg_objs

A list of linear expressions for each argument.

dim

A vector representing the dimensions of the resulting expression.

data

A list of additional data required by the atom.

## Value

A list of list(LinOp for objective, list of constraints), where LinOp is a list representing the linear operator.