how do i clear jenkins cache using jenkinsfile code example

Example 1: how do i clear jenkins cache using jenkinsfile

def jobName = "python-devops"  
def job = Jenkins.instance.getItem(jobName)  
job.getBuilds().each { it.delete() }  
job.nextBuildNumber = 1   
job.save()

Example 2: how do i clear jenkins cache using jenkinsfile

println(Jenkins.instance.pluginManager.plugins)