diff --git a/knife_edge.py b/knife_edge.py
index 811502cbe34c1a2852071c8ef7d97487c93abe56..4fffc94adb9f0d1e6cadaa4b73b22f46d0ee7d3a 100644
--- a/knife_edge.py
+++ b/knife_edge.py
@@ -63,4 +63,4 @@ def knife_edge(nrun, axisKey='scannerX', signalKey='FastADC4peaks', p0=None, plo
         plt.ylabel(signalKey)
         plt.xlabel(axisKey + '-position [mm]')
         plt.tight_layout()
-    return np.array(popt[1], pcov[1,1]**0.5)
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+    return np.array([popt[1], pcov[1,1]**0.5])
\ No newline at end of file