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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 create_srpm(dist='el7'):
 """Create an srpm Requires that sources are available in local directory dist: set package dist tag (default: el7) """

    if not RPM_AVAILABLE:
        raise RpmModuleNotAvailable()
    path = os.getcwd()
    try:
        specfile = spec_fn()
        spec = Spec(specfile)
    except Exception:
        return

    rpmdefines = ["--define 'dist .{}'".format(dist),
                  "--define '_sourcedir {}'".format(path),
                  "--define '_srcrpmdir {}'".format(path)]
    rpm.addMacro('_sourcedir', '.{}'.format(dist))
    # FIXME: needs to be fixed in Spec
    rpm.addMacro('dist', '.{}'.format(dist))
    module_name = spec.get_tag('Name', True)
    version = spec.get_tag('Version', True)
    release = spec.get_tag('Release', True)
    srpm = os.path.join(path,
                        "{}-{}-{}.src.rpm".format(module_name,
                                                  version,
                                                  release))

    # See if we need to build the srpm
    if os.path.exists(srpm):
        log.warn('Srpm found, rewriting it.')

    cmd = ['rpmbuild']
    cmd.extend(rpmdefines)

    cmd.extend(['--nodeps', '-bs', specfile])
    output = subprocess.check_output(' '.join(cmd), shell=True)
    log.warn(output)
    srpm = output.split()[1]
    return srpm