Maps a genome position to transcript positon"

    :param df: a Pandas dataframe
    :param field: the head of the column containing the genomic position
    :param dic: a dictionary containing for each transcript the respective bases eg. {ENST23923910:'234,235,236,1021,..'}
    :param refCol: header of the reference column with IDs, eg. 'transcript_id'

    :returns: position on transcript

def GetTransPosition(df,field,dic,refCol="transcript_id"):
    """
    Maps a genome position to transcript positon"

    :param df: a Pandas dataframe
    :param field: the head of the column containing the genomic position
    :param dic: a dictionary containing for each transcript the respective bases eg. {ENST23923910:'234,235,236,1021,..'}
    :param refCol: header of the reference column with IDs, eg. 'transcript_id'

    :returns: position on transcript
    """
    try:
        gen=str(int(df[field]))
        transid=df[refCol]
        bases=dic.get(transid).split(",")
        bases=bases.index(str(gen))+1
    except:
        bases=np.nan
    return bases