I wish to color an model  by an attribute in chimerax. The attribute is the entropy which is calculted by an external software. I wrote the entropy values of each residue in a text file (attr.txt) like the following:

attribute: entropy
match mode: 1-to-1
recipient: residues
 :1 0.0
 :2 0.0014948
 :3 0.0090952
 :4 0.0004805
 :5 0.1102497
 :6 0.0095258
 :7 0.0008226
 :8 0.0042205
 :9 0.0037255
 :10 0.0006678
 :11 0.0027988
 :12 0.0193925
 :13 0.0153925
 :14 0.0052115
 :15 0.0020136

..........

However, when I input the command "color byattr attr.txt", I get the following error information:

"No known/Registered attribute attr.txt"

Could anyone tell me what is the correct way to do this?

With many thanks.

Best regards