am"><span class="n"><span class="pre">spectrum</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">axis</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">wavenumbers_syn</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">model_type</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">'sinc'</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">lines</span></