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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 is_user(value, min=None, max=None):
 """ Check whether username or uid as argument exists. if this function recieved username, convert uid and exec validation. """


    if type(value) == str:
        try:
            entry = pwd.getpwnam(value)
            value = entry.pw_uid
        except KeyError:
            err_message = ('{0}: No such user.'.format(value))
            raise validate.VdtValueError(err_message)

        return value

    elif type(value) == int:
        try:
            pwd.getpwuid(value)
        except KeyError:
            err_message = ('{0}: No such user.'.format(value))
            raise validate.VdtValueError(err_message)

        return value

    else:
        err_message = ('Please, use str or int to "user" parameter.')
        raise validate.VdtTypeError(err_message)