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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 _assemble_regulate_activity(stmt):
 """Assemble RegulateActivity statements into text."""

    subj_str = _assemble_agent_str(stmt.subj)
    obj_str = _assemble_agent_str(stmt.obj)
    if stmt.is_activation:
        rel_str = ' activates '
    else:
        rel_str = ' inhibits '
    stmt_str = subj_str + rel_str + obj_str
    return _make_sentence(stmt_str)