How to use the victory.VictoryTheme function in victory

const dateFormat = require('dateformat');
const cloneDeep = require('lodash.clonedeep');
const React = require('react');
const ReactDOMServer = require('react-dom/server');
const V = require('victory');

const e = React.createElement;

const Theme = cloneDeep(V.VictoryTheme.grayscale);
Theme.axis.style.tickLabels.fontFamily = `'PT Sans', 'sans-serif'`;
Theme.axis.style.ticks.stroke = Theme.axis.style.axis.stroke;
Theme.axis.style.ticks.size = 5;
Theme.line.style.labels.fontFamily = `'PT Sans', 'sans-serif'`;

function render (alert) {
  const data = cloneDeep(alert.priceHistory);

  // hack to show graph if there is only one data point
  if (data.length === 1) {
    data.push(cloneDeep(data[0]));
    data[1].time = data[0].time + 1;
  }

  const times = data.map(d => d.time);
  const minTime = Math.min(...times);

key: "",
                    y: distanceKm - element.starting_value,
                    label: `Current: ${(
                      distanceKm - element.starting_value
                    ).toLocaleString()} kms`
                  },
                  {
                    key: "",
                    y: endVal - (distanceKm - element.starting_value),
                    label: `Remaining: ${(
                      endVal -
                      (distanceKm - element.starting_value)
                    ).toLocaleString()} kms`
                  }
                ]}
                theme={V.VictoryTheme.material}
                colorScale={["#2d728f", "#EEEEEE"]}
                innerRadius={70}
                labelRadius={80}
                padAngle={0}
              />

              <p>
                {" "}
                You have {moment(element.end_date).fromNow(true)} left to
                accomplish this goal!{" "}
              </p>
            
          );
        else if (
          element.goal_type === "distance" &amp;&amp;
          element.goal_value &lt;= distanceKm