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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:

def _format_pr(pr_):
    '''
    Helper function to format API return information into a more manageable
    and useful dictionary for pull request information.

    pr_
        The pull request to format.
    '''
    ret = {'id': pr_.get('id'),
           'pr_number': pr_.get('number'),
           'state': pr_.get('state'),
           'title': pr_.get('title'),
           'user': pr_.get('user').get('login'),
           'html_url': pr_.get('html_url'),
           'base_branch': pr_.get('base').get('ref')}

    return ret