coeffs (optional): Lists the coefficients associated with the members of constrs.
constrs (optional): Constraint or constraints that participate in expression. If constrs is a list, then coeffs must contain a list of the same length. If constrs is a single constraint, then coeffs must be a scalar.
An expression object.
col = Column() col = Column(3, c1) col = Column([1.0, 2.0], [c1, c2])