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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 crs_text_element(crs, feature, parent):
 """Retrieve coordinate reference system text string from definitions. Example usage: crs_text_element('EPSG:3857'). """

    _ = feature, parent  # NOQA
    crs_definition = QgsCoordinateReferenceSystem(crs)
    crs_description = crs_definition.description()
    text = crs_text['string_format'].format(crs=crs_description)
    return text