  Aims: We aim to compute the binary fraction of "classical" dwarf spheroidal
galaxies (dSphs) that are satellites of the Milky Way (MW). This value can
offer insights into the binary fraction in environments that are less dense and
more metal-poor than our own galaxy. Additionally, knowledge of the binary
fraction in dwarf galaxies is important with respect to avoiding
overestimations of their dark matter content, inferred from stellar kinematics.
  Methods: We refined an existing method from the literature, placing an
emphasis on providing robust uncertainties on the value of the binary fraction.
We applied this modified method to a VLT/FLAMES dataset for Sculptor,
specifically acquired for the purpose of velocity monitoring of individual
stars, as well as to literature datasets for other six MW "classical" dSphs. In
all cases, the targeted stars were mainly red giant branch stars (RGBs), with
expected masses of around 0.8 M$_{\odot}$. The VLT/FLAMES dataset offers the
most precise binary fractions compared to literature datasets, due to its time
baseline of 12 years, along with at least nine repeated observations for each
star.
  Results: We found that the binary fraction of Sculptor is
0.55$^{+0.17}_{-0.19}$. We find that it is important to take into account the
Roche lobe overflow for constraining the period distribution of binary stars.
In contrast to what has recently been proposed in the literature, our analysis
indicates that there is no evidence to support varying the properties of the
binary stellar population or their deviations from those established for the
solar neighborhood, based on the sample of MW dSphs analyzed here.
