def find_neighbors(ID, neighboring_matrix):
    """Filters all polygons which are actually neighbors to given polygon.

    Args:
        ID (int): ID of specific polygon under consideration.
        neighboring_matrix (dataframe): output from neighboring_polys().

    Returns:
        dataframe: dataframe containig IDs of all polygons that are actual neighbors.
    """    

    # locaties entry for polygon under consideration
    neighbours = neighboring_matrix.loc[neighboring_matrix.index == ID].T
    
    # filters all actual neighbors defined as neighboring polygons with True statement
    actual_neighbours = neighbours.loc[neighbours[ID] == True].index.values

    return actual_neighbours