electrum protocol: add support for 1.6, but keep supporting 1.4 - #10295

5     E114 indentation is not a multiple of 4 (comment)
15    E116 unexpected indentation (comment)
2     E117 over-indented
4     E121 continuation line under-indented for hanging indent
1641  E122 continuation line missing indentation or outdented
10    E123 closing bracket does not match indentation of opening bracket's line
5     E124 closing bracket does not match visual indentation
6     E125 continuation line with same indent as next logical line
50    E126 continuation line over-indented for hanging indent
59    E127 continuation line over-indented for visual indent
57    E128 continuation line under-indented for visual indent
63    E131 continuation line unaligned for hanging indent
28    E201 whitespace after '{'
6     E202 whitespace before '}'
53    E203 whitespace before ':'
1     E211 whitespace before '['
107   E221 multiple spaces before operator
44    E222 multiple spaces after operator
124   E225 missing whitespace around operator
663   E226 missing whitespace around arithmetic operator
8     E227 missing whitespace around bitwise or shift operator
71    E228 missing whitespace around modulo operator
258   E231 missing whitespace after ','
328   E241 multiple spaces after ','
120   E251 unexpected spaces around keyword / parameter equals
9     E252 missing whitespace around parameter equals
123   E261 at least two spaces before inline comment
23    E262 inline comment should start with '# '
223   E265 block comment should start with '# '
47    E266 too many leading '#' for block comment
4     E271 multiple spaces after keyword
1     E275 missing whitespace after keyword
194   E301 expected 1 blank line, found 0
153   E302 expected 2 blank lines, found 1
43    E303 too many blank lines (3)
11    E305 expected 2 blank lines after class or function definition, found 1
127   E306 expected 1 blank line before a nested definition, found 0
1     E401 multiple imports on one line
44    E402 module level import not at top of file
14750 E501 line too long (135 > 79 characters)
72    E502 the backslash is redundant between brackets
216   E701 multiple statements on one line (colon)
5     E702 multiple statements on one line (semicolon)
19    E704 multiple statements on one line (def)
10    E721 do not compare types, for exact checks use `is` / `is not`, for instance checks use `isinstance()`
48    E731 do not assign a lambda expression, use a def
38    E741 ambiguous variable name 'l'
429   F401 '.util.format_satoshis' imported but unused
5     F402 import '_' from line 23 shadowed by loop variable
131   F541 f-string is missing placeholders
202   F841 local variable 'e2' is assigned to but never used
1     F901 'raise NotImplemented' should be 'raise NotImplementedError'
34    W391 blank line at end of file
200   W503 line break before binary operator
109   W504 line break after binary operator
21190