The authors, Sune R. Bahn and Karsten W. Jacobsen, have developed an object-oriented scripting interface for a mature density functional theory (DFT) code, Dacapo, which is used to describe atomic system structure and dynamics. The interface allows users to control the code without rewriting the underlying numerical code, providing a high-level, flexible handle. The article discusses the design issues and advantages of homogeneous interfaces, emphasizing the importance of object-oriented programming in computational physics and chemistry. The authors explain how they created a Python framework around the existing file-based interface, making it accessible and extendable. They detail the process of creating modules and classes, such as the Simulation class, which acts as a container for parameters, and the ListOfAtoms class, which contains structural information. The article also covers the benefits of using Python's dynamic type checking and object-oriented features, including polymorphism and inheritance. Additionally, it discusses the integration of the interface with other codes, such as the effective medium theory (EMT) code, and the use of third-party tools like Gnuplot and VTK for data visualization. The authors conclude by highlighting the ongoing development of the interface and its potential for integrating different methods and codes in multiscale simulations.The authors, Sune R. Bahn and Karsten W. Jacobsen, have developed an object-oriented scripting interface for a mature density functional theory (DFT) code, Dacapo, which is used to describe atomic system structure and dynamics. The interface allows users to control the code without rewriting the underlying numerical code, providing a high-level, flexible handle. The article discusses the design issues and advantages of homogeneous interfaces, emphasizing the importance of object-oriented programming in computational physics and chemistry. The authors explain how they created a Python framework around the existing file-based interface, making it accessible and extendable. They detail the process of creating modules and classes, such as the Simulation class, which acts as a container for parameters, and the ListOfAtoms class, which contains structural information. The article also covers the benefits of using Python's dynamic type checking and object-oriented features, including polymorphism and inheritance. Additionally, it discusses the integration of the interface with other codes, such as the effective medium theory (EMT) code, and the use of third-party tools like Gnuplot and VTK for data visualization. The authors conclude by highlighting the ongoing development of the interface and its potential for integrating different methods and codes in multiscale simulations.