def dfs_all_values(dfs, column):
    """Find all possible values of a column in the pandas.DataFram list

    :param dfs: list of pandas.DataFrame objects to draw on the subplot
    :type dfs: list[pandas.DataFrame]
    :param column: a columns
    :type column: str
    :return: a sorted list of possible values from the column
    :rtype: list[values]
    """
    values = []
    # loop over all (pandas.DataFrame, str) pairs
    for df in dfs:
        values.extend(df[column].tolist())

    # set() removes duplicates
    # sorted() converts Set to List and sort the elements
    return sorted(set(values))