Cannot use FromPandas with string columns

[acampove]

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Description

Hi,

I seem to be unable to use FromPandas with dataframes that have a string.

Reproducer

import pandas as pd
import ROOT
import numpy as np

df = pd.DataFrame({
    'value': [1.1, 2.2, 3.3, 4.4],
    'label': ['a', 'b', 'c', 'd']
})

print(df)

rdf = ROOT.RDF.FromPandas(df)
rdf.Display().Print()

ROOT version

6.32.10

also checked in 6.34.4

Installation method

mamba

Operating system

alma9

Additional context

No response