diff --git a/lark/grammars/python.lark b/lark/grammars/python.lark
index 684193d..e73362d 100644
--- a/lark/grammars/python.lark
+++ b/lark/grammars/python.lark
@@ -10,8 +10,8 @@ DEC_NUMBER: /0|[1-9][\d_]*/i
 HEX_NUMBER.2: /0x[\da-f]*/i
 OCT_NUMBER.2: /0o[0-7]*/i
 BIN_NUMBER.2 : /0b[0-1]*/i
-FLOAT_NUMBER.2: /((\d+\.[\d_]*|\.[\d_]+)(e[-+]?\d+)?|\d+(e[-+]?\d+))/i
-IMAG_NUMBER.2: /\d+j/i | FLOAT_NUMBER "j"i
+FLOAT_NUMBER.2: /((\d+\.[\d_]*|\.[\d_]+)([Ee][-+]?\d+)?|\d+([Ee][-+]?\d+))/
+IMAG_NUMBER.2: /\d+[Jj]/ | FLOAT_NUMBER /[Jj]/
 
 
 // Comma-separated list (with an optional trailing comma)
diff --git a/lark/indenter.py b/lark/indenter.py
index 7e1263d..f5a1895 100644
--- a/lark/indenter.py
+++ b/lark/indenter.py
@@ -9,6 +9,10 @@ class DedentError(LarkError):
     pass
 
 class Indenter(PostLex):
+    OPEN_PAREN_types: list
+    CLOSE_PAREN_types: list
+    DEDENT_type: str
+
     def __init__(self):
         self.paren_level = None
         self.indent_level = None
diff --git a/lark/parse_tree_builder.py b/lark/parse_tree_builder.py
index e95003a..fa418a9 100644
--- a/lark/parse_tree_builder.py
+++ b/lark/parse_tree_builder.py
@@ -151,7 +151,7 @@ def _should_expand(sym):
     return not sym.is_term and sym.name.startswith('_')
 
 
-def maybe_create_child_filter(expansion, keep_all_tokens, ambiguous, _empty_indices):
+def maybe_create_child_filter(expansion, keep_all_tokens, ambiguous, _empty_indices: list):
     # Prepare empty_indices as: How many Nones to insert at each index?
     if _empty_indices:
         assert _empty_indices.count(False) == len(expansion)