Exposes key_values and set_key_values for PyFkTable

pineappl/src/fk_table.rs

@@ -219,6 +219,13 @@ impl FkTable {
         muf2
     }
 
+    /// Set a metadata key-value pair for this FK table.
+    pub fn set_key_value(&mut self, key: &str, value: &str) {
+        self.grid
+            .metadata_mut()
+            .insert(key.to_owned(), value.to_owned());
+    }
+
     /// Returns the x grid that all subgrids for all hadronic initial states share.
     #[must_use]
     pub fn x_grid(&self) -> Vec<f64> {

pineappl_py/src/fk_table.rs

@@ -7,6 +7,7 @@ use pineappl::convolutions::ConvolutionCache;
 use pineappl::fk_table::{FkAssumptions, FkTable};
 use pineappl::grid::Grid;
 use pyo3::prelude::*;
+use std::collections::BTreeMap;
 use std::fs::File;
 use std::io::BufReader;
 use std::path::PathBuf;
@@ -251,6 +252,31 @@ impl PyFkTable {
             .unwrap();
     }
 
+    /// Set a metadata key-value pair in the FK Table.
+    ///
+    /// Parameters
+    /// ----------
+    /// key : str
+    ///     key
+    /// value : str
+    ///     value
+    pub fn set_key_value(&mut self, key: &str, value: &str) {
+        self.fk_table.set_key_value(key, value);
+    }
+
+    /// Get metadata values stored in the grid.
+    ///
+    ///
+    /// Returns
+    /// -------
+    /// dict :
+    ///     key, value map
+    #[getter]
+    #[must_use]
+    pub fn key_values(&self) -> BTreeMap<String, String> {
+        self.fk_table.grid().metadata().clone()
+    }
+
     /// Convolve the FK table with as many distributions.
     ///
     /// # Panics