def replace_pcell_libname(pcell_script, libname):
    """Replace {libname} tag with library name
    
    Parameters
    ----------
    pcell_script : str
        Python PCell script.
    libname : str
        Library name.

    Returns
    -------
    str
        PCell script with the {libname} tag replaced by the library name.

    """
    return pcell_script.replace('{libname}', libname)