Invoking an external command in Python is a two step process:

from subprocess import call
call(["ls","-1"])

Static variables in Python are created as part of the class declaration.  By contrast, instance variables are created as part of a regular method and not a classmethod or staticmethod.

class A:
  i=3  # static variable
	
  def dosomethingregularmethod(self):
       self.k=4   # instance variable
	
# to access static variables


A.i

If you are a software developer looking for a slight change, then you have several options available. The process of software development requires multiple types of resources. A software developer performs the construction and delivery of software programs. An experienced software developer gains business knowledge, analytical skills, team management skills and communication skills. All of these skills can be used to divert your development career into a related and slightly varied role in software development.

Production Support Engineer
A developer can easily switch to the role of a Production Support Engineer. This role entails working with customers and technical teams to report, track and resolve production issues. For some, this might be an exciting opportunity to see the software application from a user’s point of view.

Engineering Manager
If you have experience in leading a team of developers, you could take the role of an Engineering Manager. This role requires managing a bigger team of developers. The Engineering Manager is also responsible for ensuring the delivery of software products and meeting the deadlines set by Product Management. You will get the opportunity to develop software, if you are inclined to do so. However, you will also take new responsibilities such as performance management, infrastructure management and vendor management.

Partner Engineer
This role requires some amount development as well as coordination with partners such as vendors and customers. The job of a Partner Engineer is to act as a middleman to help the integration of services with partners via application programming interfaces (APIs). For example, companies such as Twitter and Facebook employ Partner Engineers to integrate their services with customer websites.

Systems Analyst
Many companies offer developers with an opportunity to switch to Analyst roles. This role involves analyzing system requirements by working with business and technical teams. Many Systems Analysts also work on reviewing, developing and testing application code. This role is suitable for developers with strong analytical skills.

QA Automation Engineer
This role is responsible for automating test cases with the help of tools such as Java, Ruby and Selenium. This role is ideal for people with prior development experience. QA Automation Engineers work with developers and product managers to define test cases, and to automate and run the test cases. In this role, you will get the opportunity to work on back-end as well as front-end automation tasks. You will remain in touch with programming languages as well as database technologies.

Database Analyst
Most people gain significant amount of knowledge on databases while working as a software developer. This will help you to switch your role into a Database Analyst. A Database Analyst analyzes database issues, reviews performance problems, writes database scripts and runs queries. This role also provides a path to become a Database Administrator, if you are interested.

Deployment Engineer
This role is responsible for deploying the code developed by software engineers. You may not be developing application programs in this role. However, you will be responsible for code deployments, pushing the code into test and production environments.

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